U.S. patent application number 12/854146 was filed with the patent office on 2011-04-14 for use of utp for the diagnosis of stenoses and other conditions of restricted blood flow.
Invention is credited to Jaya Brigitte Rosenmeier.
Application Number | 20110085977 12/854146 |
Document ID | / |
Family ID | 43027659 |
Filed Date | 2011-04-14 |
United States Patent
Application |
20110085977 |
Kind Code |
A1 |
Rosenmeier; Jaya Brigitte |
April 14, 2011 |
Use of UTP for the diagnosis of stenoses and other conditions of
restricted blood flow
Abstract
The present invention relates to methods for determining whether
blood flow is restricted in a blood vessel of an individual
suspected of compromised blood flow in the vessel, the method
comprising the steps of delivering UTP, a derivative thereof, or a
salt thereof to the vessel, assessing blood flow quantitatively in
the vessel by obtaining a value that correlates to blood flow in
said vessel, comparing the obtained value with a reference value,
and determining whether the individual has compromised blood flow
based on the results of the comparison. The invention also provides
for methods of diagnosing atherosclerotic and ischemic heart
diseases using UTP, a derivative thereof, or a salt thereof, as
well as methods for inducing maximal hyperemia for diagnostic
purposes.
Inventors: |
Rosenmeier; Jaya Brigitte;
(Hellerup, DK) |
Family ID: |
43027659 |
Appl. No.: |
12/854146 |
Filed: |
August 10, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61232518 |
Aug 10, 2009 |
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61357857 |
Jun 23, 2010 |
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Current U.S.
Class: |
424/9.1 |
Current CPC
Class: |
A61B 5/026 20130101;
A61K 51/04 20130101; A61K 51/0478 20130101; A61P 9/10 20180101 |
Class at
Publication: |
424/9.1 |
International
Class: |
A61K 49/00 20060101
A61K049/00 |
Claims
1. A method for determining whether blood flow is restricted in a
blood vessel of an individual suspected of compromised blood flow
in the vessel, the method comprising: (a) delivering UTP, a
derivative thereof, or a salt thereof to said vessel, (b) assessing
blood flow quantitatively in the vessel by obtaining a value that
correlates to blood flow in said vessel, (c) comparing the obtained
value with a reference value, and (d) determining whether the
individual has compromised blood flow based on the results of the
comparison.
2. The method of claim 1, wherein the individual is suffering or
suspected to be suffering from a disease or disorder selected from
the group consisting of obesity, hypertension, vasculitis,
increased thrombotic risk, hypercholesterolemia, atherosclerosis,
diabetic complications, or vascular stenosis.
3. The method of claim 1 wherein said individual is suffering or is
suspected to be suffering of Peripheral Artery Disease (PAD),
coronary atherosclerosis, atherosclerosis, renal artery stenosis,
or ischemic heart disease.
4. The method of claim 1, wherein the reference value is obtained
by measuring blood flow in another similar vessel of said
individual.
5. The method of claim 1, wherein blood flow is assessed by FFR,
CFR, MAP, or APV measurement.
6. The method of claim 1, wherein UTP, a derivative thereof, or a
salt thereof is delivered by in situ infusion.
7. The method of claim 1, wherein the UTP, a derivative thereof, or
a salt thereof is selected from the group consisting of UTP,
UTP.gamma.S, MRS2498, uridine 5'-trisphosphate tris salt, uridine
5'-trisphosphate salt dihydrate, uridine 5'-trisphosphate salt
solution, uridine 5'-trisphosphate salt hydrate,
uridine-.sup.13C.sub.9, .sup.15N.sub.2 5'-trisphosphate sodium salt
solution, uridine-.sup.15N.sub.2 5'-trisphosphate sodium salt
solution, uridine 5'-triphosphate trisodium salt hydrate,
uridine-.sup.13C.sub.9, .sup.15N.sub.2 5'-triphosphate sodium salt
solution, uridine-.sup.15N.sub.2 5'-triphosphate sodium salt
solution, 2-diuridine tetraphosphate, thioUTP tetrasodium salt,
denufosol tetrasodium, and UTP.gamma.S trisodium salt.
8. The method of claim 1, wherein the UTP, a derivative thereof, or
a salt thereof, is administered at a rate of infusion from about 50
to about 400 .mu.g of the compound per minute.
9. The method of claim 1, wherein the UTP, a derivative thereof, or
a salt thereof, is administered via continuous intravenous
infusion, intracoronary infusion, drip infusion, intracoronary
bolus injection, a guiding catheter, or an IC microcatheter.
10. The method of claim 9, wherein the UTP, a derivative thereof,
or a salt thereof, is administered via a guiding catheter or an IC
microcatheter.
11. The method of claim 9, wherein the UTP, a derivative thereof,
or a salt thereof, is administered at a rate of infusion is about
80 to about 360 .mu.g of the compound per minute.
12. A method for determining whether blood flow is restricted in a
blood vessel of an individual suspected of compromised blood flow
in the vessel, the method comprising: (a) delivering UTP, a
derivative thereof, or a salt thereof to said vessel, (b) assessing
blood flow quantitatively in the vessel by obtaining a value that
correlates to blood flow in said vessel, (c) comparing the obtained
value with a reference value, and (d) determining whether the
individual has compromised blood flow based on whether there is a
difference between the obtained value and the reference value
indicative of a reduction in blood flow relative to a healthy
vessel.
13. A method for determining whether blood flow in a blood vessel
of an individual suspected of compromised blood flow in the vessel
is restricted, the method comprising: (a) delivering UTP, a
derivative thereof, or a salt thereof to said vessel of an
individual suspected of having an atherosclerotic or ischemic
disease, (b) assessing blood flow quantitatively in the vessel by
obtaining a value that correlates to blood flow in said vessel, (c)
comparing the obtained value with a reference value, and (d)
determining whether the individual has compromised blood flow based
on the results of the comparison.
14. A method for determining blood flow in a blood vessel
comprising: (a) delivering UTP, a derivative thereof, or a salt
thereof to an individual suspected of having a vessel with
compromised blood flow, (b) assessing blood flow quantitatively in
the vessel by obtaining a value that correlates to blood flow in
said vessel, (c) comparing the obtained value with a reference
value, and (d) determining whether the individual has compromised
blood flow based on the results of the comparison.
15. The method of claim 14, wherein the compromised blood flow
results from a blood clot or stenosis.
16. The method of claim 14, wherein the UTP, a derivative thereof,
or a salt thereof, is administered via a guiding catheter or an IC
microcatheter.
17. A method for diagnosing a disease selected from the group
consisting of Peripheral Artery Disease (PAD), coronary
atherosclerosis, and ischemic heart disease comprising: (a)
delivering UTP, a derivative thereof, or a salt thereof to an
individual suspected of having said disease, (b) assessing blood
flow quantitatively in the vessel by obtaining a value that
correlates to blood flow in said vessel, (c) comparing the obtained
value with a reference value, and (d) determining whether the
individual has compromised blood flow based on the results of the
comparison.
18. A method for the induction of maximal coronary hyperemia
comprising delivering to an individual in need thereof UTP, a
derivative thereof, or a salt thereof.
19. A kit for determining blood flow in a blood vessel comprising:
(a) UTP, a derivative thereof, or a salt thereof as an active
diagnostic ingredient, and (b) instructions for the use thereof in
an individual with suspected compromised blood flow.
20. The kit of claim 19, wherein the kit further comprises a
guiding catheter or microcatheter.
21. The kit of claim 19, wherein the kit further comprises a
physiologically acceptable aqueous carrier.
22. The kit of claim 21, wherein the physiologically acceptable
aqueous carrier is saline.
23. The kit of claim 21, wherein the physiologically acceptable
aqueous carrier and active diagnostic ingredient are provided in
separate containers.
24. A diagnostic composition comprising UTP, a derivative thereof,
or a salt thereof in a pharmaceutically acceptable aqueous carrier
suitable for administration into a human patient, wherein the
composition contains from about 50 to about 400 .mu.g/ml of UTP, a
derivative thereof, or a salt thereof.
25. The diagnostic composition of claim 24, wherein the composition
is delivered to an individual in need thereof in a total volume of
about 2 ml to about 10 ml
26. A method for diagnosing renal artery stenosis comprising: (a)
delivering UTP, a derivative thereof, or a salt thereof to an
individual suspected of having said disease, (b) assessing blood
flow quantitatively in the vessel by obtaining a value that
correlates to blood flow in said vessel, (c) comparing the obtained
value with a reference value, and (d) determining whether the
individual has compromised blood flow based on the results of the
comparison.
27. A method for screening individuals at risk of developing an
atherosclerotic or ischemic disease comprising: (a) delivering UTP,
a derivative thereof, or a salt thereof to the individual, (b)
assessing blood flow quantitatively in the vessel by obtaining a
value that correlates to blood flow in said vessel, (c) comparing
the obtained value with a reference value, and (d) determining
whether the individual has compromised blood flow based on the
results of the comparison.
28. A method for measuring fractional flow reserve (FFR)
comprising: (a) delivering UTP, a derivative thereof, or a salt
thereof to a blood vessel in escalating stepwise doses, (b)
monitoring pressure across the blood vessel until distal pressure
reaches a minimum value, wherein the minimum value corresponds to
maximal blood flow.
29. The method of claim 28, wherein UTP, a derivative thereof, or a
salt thereof is delivered by intracoronary infusion.
30. The method of claim 28, wherein FFR measures blood flow in a
coronary artery.
31. The method of claim 28, wherein UTP, a derivative thereof, or a
salt thereof is administered by a FFR thermodilution catheter, a
microinfusion catheter or guiding catheter.
32. The method of claim 28, wherein the escalating stepwise doses
are 20, 40, 80, 160, 240, 360, and 400 .mu.g/min.
33. The method of claim 1 wherein the amount of UTP, UTP salt or
UTP derivative is effective to create maximal hyperemia in said
vessel.
Description
CROSS-REFERENCE TO PRIOR APPLICATION
[0001] This application claims the benefit of U.S. Provisional
application Ser. No. 61/232,518, filed Aug. 10, 2009 and Ser. No.
61/357,857 filed Jun. 23, 2010, both of which are incorporated by
reference herein in their entirety.
FIELD OF INVENTION
[0002] The present invention relates to methods for determining
whether blood flow is restricted in a blood vessel of an individual
suspected of compromised blood flow in the vessel using UTP, a
derivative thereof, or a salt thereof. Also, it relates to
compositions containing UTP, a derivative thereof, or a salt
thereof for use as a diagnostic agent in the foregoing methods.
BACKGROUND OF INVENTION
[0003] The potent and widespread vascular actions of purine
nucleotides and nucleosides have long been recognized. Naturally
occurring extracellular purine nucleotides and nucleosides exert
cardiovascular responses by stimulating various P1 and P2 receptors
[1,2]. Adenine nucleotides and nucleosides are used for many
diagnostic and treatment purposes in daily clinical practice such
as assessment of coronary blood flow [3-8] and as anti-arrhythmic
agents. Adenosine non-selectively activates 4 receptor subtypes:
A1, A2A, A2B, and A3. Activation of cardiac A2A and A2B adenosine
receptors vasodilates the coronary and peripheral arterial beds,
increases myocardial blood flow (MBF), and causes
sympathoexcitation, but also results in mast cell degranulation and
bronchial constriction. Nevertheless, intracoronary and intravenous
adenosine are employed in the clinic for assessment of fractional
flow reserve (FFR).
[0004] Uridine 5-triphosphate (UTP) is also a naturally occurring
compound in the circulation and is discharged during acute
myocardial infarction. UTP stimulates P2Y2 and P2Y4 receptors,
where the first are predominant in the human cardiovascular tree.
UTP is highly selective for this receptor.
[0005] Previous assumptions underlying the use of UTP in treatment
of cardiovascular disease have proved inaccurate in vivo. It was
demonstrated in 2004 and 2008 [9, 10], by using local infusion of
ATP and UTP, that these two agents were the only registered
metabolites capable of opposing sympathetic vasoconstriction and
concomitantly increasing blood flow (85% and 60% of maximum in the
leg during hard exercise, respectively). However, the present
inventor, using systemic infusion of UTP in pigs, has found that
UTP can only maximally lower mean arterial pressure by 30% (Example
4), which is substantially less than that achieved by ATP because
ATP can produce limitless lowering of blood pressure. Therefore,
ATP is more potent than UTP systemically as well as locally in the
healthy leg, although both ATP and UTP were shown previously to be
equipotent in the peripheral vascular system for the P2Y2 receptor
in the arms of humans [11].
[0006] The higher potency of ATP compared to UTP in the normal
healthy leg was attributed to the degradation of ATP to ADP, AMP,
and adenosine. These degradation products, in conjunction with ATP,
could contribute to elevate blood flow higher than that achieved by
UTP, which does not have any vasoactive degradation products. Thus,
a comparison of the relative vasoactive potencies of exogenous
nucleotides and adenosine revealed the following rank order: ATP
(100)=UTP (100)>>adenosine (5.8)>ADP (2.7)>AMP (1.7),
but only for blood flows around 3.5 Lmin.sup.-1 [9].
[0007] Comparative studies in the human leg of healthy and diabetic
patients showed that UTP>>ATP with regard to vasodilation in
legs of elderly patients and patients with type 2 diabetes [12].
This is clearly in contrast to previous findings, but is more
clinically relevant as most cardiac patients are older.
Interestingly, the discrepancy in vasoactive potency was not due to
an up-regulation of the P2Y2 receptor, suggesting that
up-regulation of other ATP-related (but not UTP) vasoconstrictive
receptors must be relevant when people are of advanced age and poor
general health. However, recent studies have shown that the ability
to oppose sympathetic vasoconstriction during exercise is intact in
patients with type 2 diabetes, suggesting that previous assumptions
of a crucial involvement of the P2Y2 receptor in functional
sympatholysis are inaccurate [9]. This conclusion is also supported
by another study by the present inventor in pigs where ADP or UTP
was infused during myocardial infarction. In that study, UTP
increased the infarct area during acute myocardial infarction,
whereas ADP diminished it (unpublished results). This suggests a
pharmacological cardioprotective effect of ADP, but a detrimental
effect of UTP, suggesting that caution must be exercised when using
UTP in clinically acute conditions. Therefore, the previous
assumptions in patent application WO 2007/065437 relating to the
regulation of purinergic receptor activity to modulate vascular
tone, particularly for treating hemodynamic conditions by
overriding vasoconstriction activity, which could potentially have
clinical applications for treatment with UTP agonists or
antagonists, is incorrect.
[0008] In contrast to the vasodilating properties associated with
UTP mentioned above, UTP has also been described to be a potent
vasoconstrictor in the coronary circulation. Of particular note are
the studies relating to human coronary arteries and bypass vessels
[13-15]. In these studies, both UTP and UTP.gamma.S induced
contractions in coronary arteries and the internal mammary artery
in heart transplant patients, suggesting that P2Y2 receptors are
important contractile receptors. UTP.gamma.S also induced
contractions in the saphenous vein. Given that prolonged treatment
with UTP has been shown to induce smooth muscle proliferation in
vitro, it can be speculated that in case of endothelial dysfunction
(such as with coronary artery disease), extracellular nucleotides
derived from the blood may reach smooth muscle cells (SMCs),
leading to UTP-mediated vasoconstriction of P2Y2 receptors. In
human coronary arteries, the P2Y2-subtype has been presumed to play
a major role in this speculated constriction [14, 15]. This is also
seen in animal studies [16, 17]. In pigs, the P2Y2 receptor is
up-regulated in SMCs of in vivo stented coronary arteries to
mediate the mitogenic effects of nucleotides [18]. Therefore, the
P2Y2 receptors are suspected to take part in the pathophysiological
genesis of potentially life-threatening vasospasms [15].
[0009] Besides being looked at as evoking coronary vasoconstriction
of damaged vessels, extracellular nucleotides have also been
implicated to play an important role in the development of
inflammatory vascular disease [19,20]. Seye et al. showed that UTP,
acting at P2Y2 receptors, promoted intimal hyperplasia of collared
rabbit carotid arteries [21]. In an animal model, porcine P2Y2
receptors were found to be overexpressed in stented coronaries and
to play a distinct mitogenic role there [18]. It has thus been
accepted that vascular remodeling, facilitated by extracellular
nucleotides, is a key step in the genesis of cardiovascular and
cerebrovascular disease, potentially culminating in
life-threatening states of stroke or heart attack. Therefore, no
preceding clinical studies have ever been attempted involving in
vivo coronary infusion of UTP in humans, because this compound, for
all the above mentioned reasons, was believed to be hazardous to
humans.
[0010] Angiographic assessment of coronary artery disease (CAD) has
guided cardiac therapy for more than 30 years, however even
experienced angiographers are unable to reliably assess lesion
severity because angiography has significant intra-observer and
inter-observer variability and is not a physiological assessment,
but merely a visual one. Recent studies, such as the COURAGE trial,
have re-emphasized what all current medical guidelines recommend:
that for low risk patients, even those experiencing angina, optimal
medical therapy should be the initial treatment. For those patients
whose disease progresses, or for whom chest pain is not alleviated,
revascularization, either through angioplasty and stenting or
surgery, should be performed.
[0011] The new diagnostic tool fractional Flow Reserve (FFR) helps
physicians to decide whether to intervene on a stenosis (i.e.,
abnormal narrowing of blood vessels) or not. Achievement of maximal
hyperemia of coronary microcirculation is a prerequisite for the
exact assessment of FFR in order to minimize the effect of
microvascular resistance. Thus, the higher the flow, the larger the
pressure drop across the stenotic vessel, i.e., the lower the FFR.
For accurate FFR measurements, achievement of maximal hyperemia is
imperative for minimizing the effect of microvascular resistance.
Only at maximal hyperemia is flow and pressure linearly correlated.
If there is only suboptimal hyperemia, the FFR index underestimates
the functional severity of coronary stenosis. This can lead to
injurious outcomes [22]. Therefore, it is crucial for clinical
decision making, that the FFR response is accurate, otherwise over-
or under-treatment of patients will occur, leading to higher
mortality rates and more expensive treatment regimens.
[0012] The preferred standard hyperemic agent used today for
inducing coronary hyperemia is adenosine. However, adenosine use is
associated with side effects even with local infusions. For
example, adenosine causes dyspnea and angina in nearly all
patients, as well as second-degree AV block in some patients.
Adenosine use is also associated with contraindications such as
asthma, COPD, angina, hypotension, 2.sup.nd or 3.sup.rd-degree AV
block, and sinus node dysfunction; and the need for abstinence from
caffeine in order to get an accurate hyperemic assessment, because
caffeine blocks P1 receptors, which are the vasodilatatory
receptors the adenine compounds function through [23].
[0013] Given the foregoing limitations associated with the use of
adenine-related compounds (e.g., adenosine and ATP) as hyperemic
agents, more potent hyperemic agents with fewer side effects would
be beneficial for diagnosing compromised blood flow in blood
vessels.
SUMMARY OF THE INVENTION
[0014] The present invention is predicated on the finding of the
present inventor that UTP is a better vasodilator than other
clinically used vasodilators: adenosine, ATP and NO, which are all
equipotent in situations where patients suffer from coronary artery
disease. Thus, although UTP may not be used as a therapeutic
because it rapidly desensitizes P2Y2 receptors, may cause
endothelial cell proliferation which leads to atherosclerosis
during prolonged exposure, and has too short a terminal half-life
(20 seconds), it can surprisingly be used as an optimal diagnostic
agent. This is supported by the evidence (presented in Examples 2
and 3) in humans, who were being evaluated for potential coronary
atherosclerosis, showing the much higher potency of UTP:
UTP>>ado (=ATP) in terms of vasodilator activity. In this
study, it was shown that UTP more effectively lowers FFR than
adenosine, allowing for more accurate maximal coronary hyperemia to
be achieved. This was the first use of UTP in the context of in
vivo coronary circulation. In fact, previous in vitro studies
demonstrated that UTP induces vasoconstriction, which would
diminish coronary perfusion. Thus, the finding that UTP can induce
hyperemia in patients with suspected endothelial dysfunction is
surprising.
[0015] In contrast to ATP, UTP is highly receptor selective and
degraded rapidly (terminal half-life: about 20 sec) in the
circulation, rendering an inactive degradation product. Thus, it
has no long-term effects. UTP can easily be applied to patients
that are in a stable clinical condition or during recurrent angina
attacks. Surprisingly, the present inventor also found that UTP is
a more potent vasodilator than adenosine and ATP in both peripheral
circulation of diabetics and in the coronary circulation of
patients with coronary artery disease. Thus, UTP induces maximal
hyperemia to a greater extent than both adenosine and ATP. This is
an important finding given that maximal hyperemia is important, for
example, in the exact measurement of FFR in order to minimize the
effect of microvascular resistance.
[0016] The advantages of using UTP as a diagnostic therefore
include its specific affinity for the P2Y2 receptor, which makes it
more receptor selective than other diagnostic agents, UTP (unlike
ATP) does not have a degradation product which is vasoactive, and
no abstinence from caffeine is required for accurate hyperemic
assessment. It reaches the steady state faster and acts rapidly
(time to peak, 5 s), it is easy to use, lacks significant side
effects, has a terminal half-life of 20 s, has no obvious
contraindications, and can be used for patients who have
contraindications to the use of adenosine due to, for example,
arrhythmia, COPD, or asthma. For the foregoing reasons, UTP is an
ideal hyperemic agent for use in diagnosing compromised blood flow
in blood vessels.
[0017] The inventor has found that UTP, a derivative thereof, or a
salt thereof (as further defined below), can be used to determine
whether blood flow is restricted in a blood vessel of an individual
suspected of compromised blood flow in the vessel, by mimicking the
increased blood flow observed during exercise. Accordingly,
compromised blood flow can be determined with high accuracy even in
individuals at rest. Thus, the method is useful for determining
compromised blood flow in any individual, even in individuals who
should not or for whom it is undesirable to undergo exercise
testing.
[0018] The present invention is believed to represent the first
diagnostic use of UTP, a derivative thereof, or a salt thereof.
Consequently, in one aspect, the invention relates to compositions
containing an effective amount of UTP, a derivative thereof or a
salt thereof for use as a diagnostic agent in assessing blood
flow.
[0019] By determining that blood flow is compromised in a blood
vessel, preferably an artery of an individual with suspected
compromised blood flow, hemodynamic conditions caused by
compromised blood flow, particularly but not exclusively stenosis,
may be treated more effectively. In particular, stenosis may be
recognised before any adverse cardiovascular events, such as
myocardial infarction, stroke, and/or death has occurred, providing
an opportunity for prophylactic treatment of, for example, renal
artery disease, coronary atherosclerosis, ischemic heart disease,
or peripheral artery disease (PAD).
[0020] Accordingly, in one aspect, the invention relates to a
method for determining whether blood flow is restricted in a blood
vessel of an individual suspected of compromised blood flow in the
vessel, the method comprising: [0021] (a) delivering UTP, a
derivative thereof, or a salt thereof to said vessel, [0022] (b)
assessing blood flow quantitatively in the vessel by obtaining a
value for that indicates or correlates to blood flow in said
vessel, [0023] (c) comparing the obtained value with a reference
value, and [0024] (d) determining whether the individual has
compromised blood flow based on the results of the comparison.
[0025] In one embodiment of the above method, the individual is
suffering or suspected to be suffering from obesity, hypertension,
vasculitis, increased thrombotic risk, hypercholesterolemia,
atherosclerosis, diabetic complications, or vascular stenosis. In
another embodiment, the individual is suffering from Peripheral
Artery Disease (PAD), coronary atherosclerosis, atherosclerosis,
renal artery stenosis, or ischemic heart disease.
[0026] In another embodiment of the above method, the UTP,
derivative thereof, or salt thereof is UTP, UTP.gamma.S, MRS2498,
uridine 5'-trisphosphate tris salt, uridine 5'-trisphosphate salt
dihydrate, uridine 5'-trisphosphate salt solution, uridine
5'-trisphosphate salt hydrate, uridine-.sup.13C.sub.9,
.sup.15N.sub.2 5'-trisphosphate sodium salt solution,
uridine-.sup.15N.sub.2 5'-trisphosphate sodium salt solution,
uridine 5'-triphosphate trisodium salt hydrate,
uridine-.sup.13C.sub.9, .sup.15N.sub.2 5'-triphosphate sodium salt
solution, uridine-.sup.15N.sub.2 5'-triphosphate sodium salt
solution, 2-diuridine tetraphosphate, thioUTP tetrasodium salt,
denufosol tetrasodium, or UTP.gamma.S trisodium salt. Infusion of
UTP, a derivative thereof, or a salt thereof, can be infused at,
for example, from about 50 to about 400 .mu.g of the compound per
minute.
[0027] In yet another embodiment, the reference value is obtained
by measuring blood flow in another similar vessel of said
individual. Blood flow is measured, for example, by FFR, CFR, MAP,
or APV measurement. In yet another embodiment, delivery occurs by
in situ infusion. Delivery can also occur via continuous
intravenous infusion, intracoronary infusion, drip infusion,
intracoronary bolus injection, guiding catheter, or an IC
microcatheter, preferably a guiding catheter or IC
microcatheter.
[0028] In another aspect, the invention relates to a method for
determining whether blood flow is restricted in a blood vessel of
an individual suspected of compromised blood flow in the vessel,
the method comprising: [0029] (a) delivering UTP, a derivative
thereof, or a salt thereof to said vessel, [0030] (b) assessing
blood flow quantitatively in the vessel by obtaining a value that
correlates to blood flow in said vessel, [0031] (c) comparing the
obtained value with a reference value, and [0032] (d) determining
whether the individual has compromised blood flow based on whether
there is a difference between the obtained value and the reference
value indicative of a reduction in blood flow relative to a healthy
vessel.
[0033] In yet another aspect, the invention relates to a method for
determining whether blood flow in a blood vessel of an individual
suspected of compromised blood flow in the vessel is restricted,
the method comprising: [0034] (a) delivering UTP, a derivative
thereof, or a salt thereof to said vessel of an individual
suspected of having an atherosclerotic or ischemic disease, [0035]
(b) assessing blood flow quantitatively in the vessel by obtaining
a value that correlates to blood flow in said vessel, [0036] (c)
comparing the obtained value with a reference value, and [0037] (d)
determining whether the individual has compromised blood flow based
on the results of the comparison.
[0038] In yet another aspect, the invention relates to a method for
determining blood flow in a blood vessel comprising: [0039] (a)
delivering UTP, a derivative thereof, or a salt thereof to an
individual suspected of having a vessel with compromised blood
flow, [0040] (b) assessing blood flow quantitatively in the vessel
by obtaining a value that correlates to blood flow in said vessel,
[0041] (c) comparing the obtained value with a reference value, and
[0042] (d) determining whether the individual has compromised blood
flow based on the results of the comparison.
[0043] In a further aspect, the invention relates to a method for
diagnosing a disease selected from the group consisting of
Peripheral Artery Disease (PAD), coronary atherosclerosis, and
ischemic heart disease comprising: [0044] (a) delivering UTP, a
derivative thereof, or a salt thereof to an individual suspected of
having said disease, [0045] (b) assessing blood flow quantitatively
in the vessel by obtaining a value that correlates to blood flow in
said vessel, [0046] (c) comparing the obtained value with a
reference value, and [0047] (d) determining whether the individual
has compromised blood flow based on the results of the
comparison.
[0048] In yet another aspect, the invention relates to a method for
the induction of maximal hyperemia comprising administering to an
individual in need thereof UTP, a derivative thereof or a salt
thereof. In one embodiment, the hyperemia is coronary
hyperemia.
[0049] A further aspect of the invention relates to a kit for
determining blood flow in a blood vessel comprising: (a) UTP, a
derivative thereof, or a salt thereof as an active diagnostic
ingredient, and (b) instructions for the use thereof in an
individual with suspected compromised blood flow. In one
embodiment, the kit further comprises a microcatheter or guiding
catheter. In another embodiment, the kit further comprises a
physiologically acceptable aqueous carrier, preferably saline. In a
further embodiment, the physiologically acceptable aqueous carrier
and the active diagnostic ingredient are provided in separate
containers.
[0050] In another aspect, the invention relates to a diagnostic
composition comprising UTP, a derivative thereof, or a salt thereof
in a pharmaceutically acceptable aqueous carrier suitable for
administration into a human patient, wherein the composition
contains from about 50 to about 400 .mu.g/ml of UTP, a derivative
thereof, or a salt thereof. In one embodiment, the diagnostic
composition containing an effective amount of the diagnostic
reagent is delivered to an individual in need thereof in a total
volume of about 2 ml to about 10 ml to induce hyperemia,
particularly maximal hyperemia.
[0051] In yet another aspect, the invention relates to a method for
diagnosing renal artery stenosis comprising: [0052] (a) delivering
UTP, a derivative thereof, or a salt thereof to an individual
suspected of having said disease, [0053] (b) assessing blood flow
quantitatively in the vessel by obtaining a value that correlates
to blood flow in said vessel, [0054] (c) comparing the obtained
value with a reference value, and [0055] (d) determining whether
the individual has compromised blood flow based on the results of
the comparison.
[0056] In yet another aspect, the invention relates to a method for
screening individuals at risk of developing an atherosclerotic or
ischemic disease comprising: [0057] (a) delivering UTP, a
derivative thereof, or a salt thereof to the individual, [0058] (b)
assessing blood flow quantitatively in the vessel by obtaining a
value that correlates to blood flow in said vessel, [0059] (c)
comparing the obtained value with a reference value, and [0060] (d)
determining whether the individual has compromised blood flow based
on the results of the comparison.
[0061] In yet another aspect, the invention relates to a method for
measuring fractional flow reserve (FFR) comprising: [0062] (a)
delivering UTP, a derivative thereof, or a salt thereof to a blood
vessel in escalating stepwise doses, [0063] (b) monitoring pressure
across the blood vessel until distal pressure reaches a minimum
value, wherein the minimum value corresponds to maximal blood
flow.
[0064] In one embodiment, FFR measures blood flow in a coronary
artery. In another embodiment, UTP, a derivative thereof, or a salt
thereof is delivered by a delivery device, such as a microcatheter
or guiding catheter. In yet another embodiment, UTP, a derivative
thereof, or a salt thereof is delivered by intracoronary infusion.
In yet a further embodiment, the escalating stepwise doses are 20,
40, 80, 160, 240, 360, and 400 .mu.g/min.
BRIEF DESCRIPTION OF DRAWINGS
[0065] FIG. 1 is a graph showing mean FFR following intracoronary
infusion in a guiding catheter of UTP versus adenosine in humans
with coronary artery disease. This graph demonstrates that UTP is
superior to adenosine for lowering the FFR ratio (p=0.003). The FFR
is expressed as the mean of the 23 subjects.
[0066] FIG. 2 is a graph showing the patients' individual
fractional flow reserve (FFR) following intracoronary infusion of
UTP versus adenosine in humans with angiographic stenosis.
[0067] FIG. 3 is a graph showing individual mean heart rate
following intracoronary infusion of BL ado, adenosine, BL UTP or
UTP.
[0068] FIG. 4 is a graph showing the patients' individual mean
arterial pressure (MAP) and heart rate following intracoronary
infusion of baseline (BL) ado, adenosine, BL UTP or UTP.
[0069] FIG. 5 is a graph showing mean FFR and average peak velocity
(flow) response during micro-catheter infusion of adenosine and
UTP. The graph clearly demonstrates that at any given equipotent
infusion, UTP>adenosine and adenosine never reaches as low an
FFR as UTP.
[0070] FIGS. 6A through 6D are graphs showing hemodynamic variables
(pulmonary vascular resistance, systemic vascular resistance, leg
blood flow and leg vascular conductance) during systemic UTP
infusion in comparison to adenosine, ATP, and ADP. UTP increases
blood flow and leg vascular conductance much more than the other
compounds, making it suitable for assessment of peripheral artery
disease because the blood flow increase may simulate exercise.
[0071] FIGS. 7A through 7D are graphs show hemodynamic variables
(mean arterial pressure, cardiac output, heart rate and stroke
volume) during systemic UTP infusion in comparison to adenosine,
ATP and ADP. UTP does not lower blood pressure as much as the other
compounds but increases cardiac output and HR, more resembling
exercise, thus making it a suitable stress agent for studies
involving myocardial perfusion imaging.
[0072] FIG. 8 is a graph showing that use of UTP alters clinical
decision making more than adenosine because it determines the FFR
more accurately. (n=23). This would lead to a diagnostic
advantage.
[0073] FIG. 9 is a diagram of indications and methods contemplated
to be within the scope of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0074] The term "hypertension", when used herein, refers to high
blood pressure. This generally means that the systolic blood
pressure is consistently over 140 and/or the diastolic blood
pressure is consistently over 90. Hypertension is when either or
both of the systolic blood pressure and the diastolic blood
pressure are too high.
[0075] "Ischemic heart disease" or myocardial ischemia as used
herein refers to a disease characterized by reduced blood supply to
the heart muscle, usually due to coronary artery disease
(atherosclerosis of the coronary arteries).
[0076] A "stenosis" as used herein, is be defined as an abnormal
narrowing in a blood vessel or other tubular organ or
structure.
[0077] "Individual" or "subject" as used herein is intended to mean
any mammal, including a human, veterinary animal, (such as a farm
animal, a domestic animal), or laboratory animal (such as a rodent
or a primate).
[0078] "P2Y2 receptor" as used herein is intended to mean a G
protein-coupled extracellular nucleotide receptor associated with a
PI signalling pathway, which may be activated for example by
extracellular nucleotides.
[0079] "Normal blood flow" as used herein is intended to mean blood
flow that is uncompromised by, for example, a stenosis or a blood
clot. A standard for normal blood flow may for example be developed
by measuring the blood flow in at least 20 healthy individuals with
no suspected illnesses and determining the average.
[0080] "Compromised blood flow" as used herein is intended to mean
any abnormality in which blood flow through a vessel is lower than
normal blood flow due to a constriction, or mechanical obstruction
or inflexibility in the vessel wall, such as stenosis. Compromised
blood flow may be assessed by many parameters including but not
limited to a drop in blood pressure and may be measured in arteries
and veins as well as in functional tissue.
[0081] "Hyperemia" as used herein is intended to mean the increase
of blood flow to different tissues in the body.
[0082] "Maximal hyperemia" as used herein is intended to mean
maximal increase in blood flow, which can be induced by the
administration of modulators of the P2Y2 receptor, which according
to the present invention is UTP, derivatives thereof, or salts
thereof as further defined below. This can be measured, inter alia,
by measuring the pressure difference between the proximal end and
the distal end of a blood vessel suspected of compromised blood
flow. When using this methodology, maximal hyperemia is considered
reached when upon further supply of UTP, a UTP derivative, or a
salt thereof, the distal pressure does not change.
[0083] "Ankle-brachial index" as used herein is intended to mean
the ratio of the blood pressure in the lower legs to the blood
pressure in the arms
[0084] "Derivative" as used herein is intended to refer to
substitution(s) or modification(s) of any group or groups on UTP,
not limited to those disclosed herein, that results in a compound
that activates the P2Y2 receptor to a degree in which the ratio of
the EC50 for stimulation of the human P2Y2 receptor divided by the
EC50 for stimulation of the human P2X1 receptor is higher, such as
at least 2 fold higher, than the corresponding ratio for ATP.
Examples of such derivatives include, but not limited to,
UTP.gamma.S, MRS2498, uridine 5'-trisphosphate tris salt, uridine
5'-trisphosphate salt dihydrate, uridine 5'-trisphosphate salt
solution, uridine 5'-trisphosphate salt hydrate,
uridine-.sup.13C.sub.9, .sup.15N.sub.2 5'-trisphosphate sodium salt
solution, uridine-.sup.15N.sub.2 5'-trisphosphate sodium salt
solution, uridine 5'-triphosphate trisodium salt hydrate,
uridine-.sup.13C.sub.9, .sup.15N.sub.2 5'-triphosphate sodium salt
solution, uridine-15N.sub.2 5'-triphosphate sodium salt solution,
2-diuridine tetraphosphate, thioUTP tetrasodium salt, denufosol
tetrasodium, or UTP.gamma.S trisodium salt.
[0085] The term "significant difference" is used herein to mean
that the difference in a measured value (e.g., in amount of blood
flow determined in a subject) and a reference value is indicative
of restricted blood flow.
[0086] The term "reference value" may have different meanings
depending on context. For example, in some cases, a "reference
value" refers to the range of normal values for blood flow (which
may be assessed directly or indirectly by measuring another
variable that correlates to blood flow). Alternatively, a
"reference value" may represent the value of blood flow associated
with an abnormal condition. For example, when fractional flow
reserve is used to assess blood flow, the measured value is
pressure differential between the distal end of a stenotic blood
vessel segment under conditions of maximal hyperemia and the
reference value is the corresponding pressure differential under
similarly hyperemic conditions in the same vessel without stenosis.
The ratio of the two provides the comparison. If the ratio is 1
(and blood is actually flowing through the vessel) there is no
stenosis. It is also possible, however, for a reference value to be
a value indicating abnormality (usually a threshold value), in
which case, the comparison would show whether the measured value
has a certain relationship to the reference value (e.g., higher or
lower than the threshold abnormality value) The connotation of
"reference value" as used in a specific context will be apparent to
one of ordinary skill in the art.
[0087] "About" as used herein is intended to mean within a
statistically meaningful range of a value. Such a range can be
within an order of magnitude, preferably within 50%, more
preferably within 20%, more preferably still within 10%, and even
more preferably within 5% of a given value or range. The allowable
variation encompassed by the term "about" depends on the particular
context under study, and can be readily appreciated by one of
ordinary skill in the art. For example, "about" may reflect
experimental error or experimental variation in measurement or
interpatient differences. As a specific example, "about 20 seconds"
when referring to terminal half-life of UTP would encompass
inter-patient differences of up to 10 to 60 seconds depending upon
ectonucleotidase activity in a given patient.
[0088] "Delivery" as used herein is intended to include any
administration that causes an effective concentration of the
administered substance to be in contact with the vessel being
assessed. Included without limitation are in situ administration to
the vessel, for example, infusion using a guiding,
FFR/thermodilution catheter (PressureWire.TM. Certus (St. Jude
Medical, Inc.)) which enables simultaneous measurement of
thermo-dilution flow (via infusion of saline) and concurrent
gathering of FFR and CFR (coronary flow reserve), or a
microinfusion catheter, or systemic administration to the
bloodstream via an intravenous catheter.
[0089] "At risk" as used herein is intended to refer to individuals
with a genetic predisposition to developing a vascular disease or
individuals who have undergone a procedure to treat a vascular
disease. A genetic predisposition may, for example, be a mutation
in a gene required for normal organ function. Individuals who have
undergone a procedure to treat a disease may be at risk for
redeveloping the disease or condition, for example, restenosis.
[0090] "Fractional flow reserve" or "FFR" as used herein is
intended to mean the ratio of absolute distal pressure to proximal
pressure at maximal hyperemia. FFR is defined as an index described
as the ratio of the hyperemic flow in a stenotic artery to the
hyperemic flow in the same artery if there was no stenosis
present.
Embodiments
[0091] The methods described herein are useful in determining
compromised blood flow in an individual with suspected compromised
blood flow. Such methods mimic the increased blood flow that occurs
during exercise and are thus particularly useful in patients who
cannot undertake exercise or for whom it is less desirable to
undertake exercise.
[0092] The present invention relates to a method for determining
whether blood flow is restricted in a blood vessel of an individual
suspected of compromised blood flow in the vessel, the method
comprising the steps of: (a) delivering UTP, a derivative thereof,
or a salt thereof to said vessel, (b) assessing blood flow
quantitatively in the vessel by obtaining a value that indicates or
correlates to blood flow in said vessel, (c) comparing the obtained
value with a reference value, and (d) whether the individual has
compromised blood flow based on the results of the comparison.
[0093] The methods of the invention may be used to determine a
suspected compromised blood flow in any blood vessel in the body.
Thus, UTP, a derivative thereof, or a salt thereof, can be
delivered to any blood vessel in the body. While the vessel is
preferably an artery, it is also possible to determine compromised
blood flow in a vein. Compromised blood flow in a vein may, for
example, be caused by a stenosis in a vein, such as a stenosis in a
graft from a bypass surgery. Within the scope of the present
invention is included measuring the blood flow across any artery.
In preferred embodiments, blood flow is measured in a coronary
artery, such as the main stem artery, right coronary artery, left
coronary artery, or any other appropriate coronary artery. In other
equally preferred embodiments, blood flow is measured in the any of
the common iliac arteries, including, but not limited to, the
femoral artery, iliac artery, or popliteal artery.
[0094] By delivering UTP, a derivative thereof, or a salt thereof,
in accordance with the method of the invention, hemodynamic
conditions can be diagnosed more effectively, with reduced or
eliminated side-effects, thereby allowing the physician to
determine the extent of abnormality, if any, more accurately, and
make a more informed choice as to the course of treatment, if any,
to be pursued.
[0095] For instance, atherosclerosis is a condition in which an
artery wall thickens as the result of a buildup of fatty materials
such as cholesterol. Atherosclerosis may give rise to various
symptoms (e.g., claudication, angina pectoris), and depending on
the symptoms, atherosclerosis may be referred to as, for example,
PAD (peripheral artery disease), coronary atherosclerosis, or TCI
(transient coronary ischemia).
[0096] Using the methods described herein, it is possible to
determine compromised blood flow, which may be an indication that
an individual is suffering from an atherosclerotic disease. The
atherosclerotic disease may be any atherosclerotic disease, for
example, coronary artery disease (CAD), Peripheral Artery Disease
(PAD), renal artery disease, vascular stenosis, aortic stenosis,
renal artery stenosis, and coronary atherosclerosis. In a
particular embodiment, the disease is CAD.
[0097] Coronary artery disease and its clinical manifestations,
such as myocardial infarction, are heritable traits. While methods
such as percutaneous coronary intervention (PCI) can successfully
treat coronary artery disease, there still remains a need for
effective diagnostic screening methods. Such diagnostic screening
methods are important not only in those afflicted with the disease,
but also to screen those at risk for developing the disease due to,
for example, restenosis or a genetic predisposition to coronary
artery disease. Such screening methods can be, but are not limited
to, FFR, CFR, MAP, APV measurements. Thus, methods of the present
invention can be applied to screen at-risk patients. These
screening methods need not be limited only to at-risk individuals,
but can, for example, be incorporated into routine heath checkups
and performed on a regular basis.
[0098] Coronary artery disease and its clinical manifestations,
including myocardial infarction, are heritable traits, consistent
with a role for inherited DNA sequence variation in conferring risk
for disease. There are many modifiable risk factors for heart
disease, such as smoking or exposure to environmental tobacco
smoke, obesity, sedentary lifestyle, diabetes, high cholesterol or
abnormal blood lipids, and hypertension. There are also
non-modifiable risk factors, such as male sex, age >50 years,
and a family history of heart disease. Many biological markers,
including elevated levels of homocysteine, are associated with an
increased risk for atherosclerosis and it has been recognized that
some people have a common defective genetic variant (called
methylenetetrahydrofolate reductase, "MTHFR") that leads to
elevated levels of homocysteine. Furthermore, certain genes are
associated with increased risk of CAD. One example is a common
polymorphism located on chromosome 9p21.3. Moreover, many loci,
including 9p21, are located in intergenic segments and elicit the
phenotype by novel mechanisms which need further elucidation.
[0099] Methods of the invention can also be used to determine
compromised blood flow in an individual who is suffering or
suspected of suffering from atherosclerosis, obesity, hypertension,
vasculitis, increased thrombotic risk, hypercholesterolemia,
diabetic complications, or vascular stenosis. Compromised blood
flow may also be an indication that an individual is suffering from
ischemic heart disease. Ischemic or ischemic heart disease (IHD),
or myocardial ischemia, is a disease characterized by reduced blood
supply to the heart muscle, usually due to coronary artery disease
(atherosclerosis of the coronary arteries).
[0100] The methods described herein are also useful for the
determination of compromised blood flow, which may also be an
indication that an individual has a blood clot. A blood clot or a
thrombus is the inappropriate activation of the hemostatic process
in an uninjured or slightly injured vessel. A thrombus in a large
blood vessel (mural thrombus) will decrease blood flow through that
vessel. In a small blood vessel (occlusive thrombus), blood flow
may be completely cut-off, resulting in death of tissue supplied by
that vessel. Thus, in one embodiment of the invention, the
suspected compromised blood flow is caused by stenosis,
particularly a coronary stenosis or any stenosis in the iliacs,
such as femoral arterial stenosis.
[0101] PAD is an atherosclerotic disease that leads to a narrowing
of the arteries, particularly in the legs. This narrowing (i.e.,
stenosis) limits the amount of blood able to pass through the
arteries, resulting in claudication. PAD is associated with
significant morbidity and mortality. Medical therapy, including
risk factor modification and antiplatelet medications, reduces
cardiovascular morbidity and mortality rates in patients with PAD.
This is why availability of safe, effective and improved
diagnostics is crucial.
[0102] Patients who cannot perform treadmill exercises are
presently tested with active pedal plantar flexion or with
inflation of a thigh cuff well above systolic pressure, in an
attempt to produce "reactive" hyperemia. Unfortunately, many
patients do not tolerate the discomfort associated with this degree
and duration of cuff inflation, so this method is rarely performed.
Therefore, pharmacological diagnostics methods which selectively
increase blood flow to the legs at rest and simulate exercise are
desirable alternatives. UTP will, when infused systemically (i.v.),
(Example 3), induce increases in cardiac output by increasing heart
rate (thus simulating exercise), thereby increasing blood flow to
the legs. This makes a stenotic lesion easily detectable by methods
for assessing blood flow. Doppler ultrasound, ankle brachial index
monitoring, and the like, as described herein. Thus, in one
embodiment, UTP, a derivative thereof, or a salt thereof, is
contemplated for use in determining whether blood flow is
restricted in a blood vessel of an individual suffering or
suspected of suffering from PAD.
[0103] Renal artery stenosis often leads to drug resistant
hypertension. Determination of renal arterial stenosis severity can
be assessed in a similar manner as coronary artery stenosis by use
of the pressure gradient and vessel diameter in the kidney [24].
Renal arteries can be examined bilaterally using the same femoral
approach as coronary FFR, and bilateral selective renal
arteriograms can be obtained. By utilizing the vasoactive effects
of UTP to induce renal hyperemia, a pressure gradient across the
renal arteries can be assessed. While adenosine lowers glomerular
filtration rate by constricting afferent arterioles and causes
dose-dependent renal vasoconstriction [25], UTP induces renal
vasodilatation [26]. Therefore, a combined catheter with pressure
and UTP infusion ensures local infusion and avoids systemic spill
over. Thus, UTP, a derivative thereof, or a salt thereof, can be
used in conjunction with the methods described herein to detect the
presence of renal stenosis.
[0104] UTP, a derivative thereof, or a salt thereof, can also be
used for the noninvasive testing for renal artery stenosis by
so-called Duplex scanning, which is a non-invasive ultrasound
method that is both sensitive and specific for detecting stenotic
lesions and the severity of the stenosis. They can then be
categorized and UTPs hemodynamic significance or renal blood flow
can be evaluated. Noninvasive diagnostic technologies continue to
advance, and as new methods are validated, the need for renal
arteriography may lessen. UTP infusion during duplex scan could be
such a diagnostic test.
[0105] Stenosis can have many causes. A stenosis within the scope
of the present invention may have any underlying cause including,
but not limited to, stenosis caused by atherosclerosis, ischemia,
infection, neoplasm, inflammation, or smoking. Thus, in a
particular embodiment, the methods described herein may be used for
the determination of compromised blood flow, which may be an
indication that an individual has a stenosis.
[0106] Methods described herein can also be applied to the
detection of hyperproliferative vascular diseases resulting from
mechanical injury, for example, that arising from the use of
stents, catheters, and the like.
UTP, UTP Derivatives, and UTP Salts
[0107] UTP is available from commercial sources (e.g., Sigma
Aldrich (St. Louis, Mo.), Trilink Biotechnologies, Inc. (San Diego,
Calif.), Axxora (Nottingham, England and Loerrach, Germany), Torcis
Bioscience (Ellisville, Mo.), Inspire Pharmaceuticals, Inc. (Durham
N.C.)). Nucleoside phosphates are also commercially available
(Sigma Aldrich) or can be made from the corresponding nucleosides
by methods known to those skilled in the art. Likewise, where
nucleosides are not commercially available, they can be made by
modifying readily available nucleosides, or by synthesis from
heterocyclic and carbohydrate precursors by methods known to those
skilled in the art.
[0108] UTP, a derivative thereof, or a salt thereof, used in the
invention is capable of stimulating the human P2Y2 receptor to a
degree in which the ratio of the EC50 for stimulation of the human
P2Y2 receptor divided by the EC50 for stimulation of the human P2X1
receptor is higher, such as at least 2 fold higher, than the
corresponding ratio for ATP.
[0109] Without being bound a specific theory, it is believed that
any UTP-related compound that has such a higher ratio as compared
to ATP provide the same advantages as ATP in that they can increase
blood flow and override increases in muscle sympathetic
vasoconstrictor activity, but do not have, or have to a lesser
degree, the disadvantages of ATP, i.e., the activation of
purinergic P2X receptors, which results in vasoconstriction and
risk of hypertension.
[0110] The formula for UTP and certain derivatives is provided
below.
##STR00001## ##STR00002## ##STR00003##
[0111] A UTP derivative has a modification or substitution of one
or more residues of UTP. Preferably, a UTP derivative is a compound
comprising UTP, wherein one or more --H are exchanged for another
group, such as one or more --H groups of the ribose moiety or one
or more --H groups of the pyrimidine moiety. Preferably said --H is
exchanged with another group selected from the group consisting of
lower alkyl, lower alkenyl, lower alkoxy, lower alcohol, --OH,
lower amines, --NH.sub.2 and halogen. Lower in this sense means
C.sub.1-6, preferably C.sub.1-3, and thus by way of example a lower
amine, may for example be C.sub.1-6-alkyl-NH.sub.2 or a
C.sub.1-6-alkenyl-NH.sub.2. Examples of UTP derivatives include,
but are not limited to, 5-substituted UTP-derivatives, for example
5, alkyl substitutions, and C'-alkyl UTP derivatives, for example,
containing alkyl groups in different positions of the ribose
moiety. Alkyl substitutions include, but are not limited to,
methyl, ethyl, proplyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl,
undecyl and dodecyl substitutions [27].
[0112] Other substitutions include, but are not limited to,
methylene, propylene, amino, sugar, any halogen and propenyl
substitutions at any uridine residue. A UTP derivative may have one
or more modifications and/or substitutions. For example, a UTP
derivative may have one modification and/or substitution, such as
two modifications and/or substitutions, for example three
modifications and/or substitutions or four modifications and/or
substitutions.
[0113] Other ribose modifications include, but are not limited to,
2'-deoxy, 2'-deoxy-2'-methoxy, 3'-deoxy-3'-methoxy,
2'-amino-2'-deoxy, 2'-azido-2'-deoxy, 2'-deoxy-2'-fluoro, arabino,
and 2'-deoxy-arabino-2'-fluoro. Some specific uridine modifications
include, but are not limited to, 5-bromo, 5-iodo, 5-methyl, 2-thio,
4-thio, 6-aza, and 3-methyl.
[0114] Other specific UTP derivatives include
5-(3-amino-1-propenyl)-2'-deoxyuridine-5'-triphosphate, tetrasodium
5-(3-amino-1-propenyl)-2'-deoxyuradine-5'-triphosphate,
tetrapotassium
5-(3-amino-1-propenyl)-2'-deoxyuridine-5'-triphosphate,
tetraammonium 5-(3-amino-1-propenyl)-2'-uridine-5'-triphosphate,
tetrasodium 5-(3-amino-1-propenyl)-2'-uridine-5'-triphosphate,
tetrapotassium 5-(3-amino-1-propenyl)-2'-uridine-5'-triphosphate,
UTP.gamma.S, .beta.,.gamma.-Imido-UTP,
.beta.,.gamma.-Methylene-UTP, .beta.,.gamma.-Difluoromethylene-UTP,
Up.sub.3U, Up.sub.4U, (N)Methanocarba-UTP, 2,2'-AnhydroUTP,
5-BrUTP, 5-Ethyl-UTP, 4-Thio-UTP and, 4-Hexylthio-UTP,
(RP)-.alpha.-thio-UTP, (SP)-.alpha.-thio-UTP,
2'-Deoxy-(RP)-.alpha.-thio-triphosphate, 9,
.alpha.,.beta.-methylene-UDP, Up4-phenyl ester, Up4-[1]glucose, and
(P1-(uridine 5')-P4-(2'-deoxycytidine 5') tetraphosphate).
[0115] In particular embodiments, the compound capable of
stimulating the P2Y2 receptor is UTP.gamma.S, MRS2498, Uridine
5'-trisphosphate tris salt, Uridine 5'-trisphosphate salt
dihydrate, Uridine 5'-trisphosphate salt solution, Uridine
5'-trisphosphate salt hydrate, Uridine-.sup.13C.sub.9,
.sup.15N.sub.2 5'-trisphosphate sodium salt solution,
Uridine-.sup.15N.sub.2 5'-trisphosphate sodium salt solution,
Uridine 5'-triphosphate trisodium salt hydrate,
Uridine-.sup.13C.sub.9, .sup.15N.sub.2 5'-triphosphate sodium salt
solution, Uridine-.sup.15N.sub.2 5'-triphosphate sodium salt
solution, 2-diuridine tetraphosphate, ThioUTP tetrasodium salt,
denufosol tetrasodium, or UTP.gamma.S trisodium salt.
[0116] In other particular embodiments. the compound used in the
invention is a compound of the general formula (I):
##STR00004##
wherein, R1 is O, S, hydroxyl, mercapto, amino or cyano, R2 is H,
Br, nothing, acyl, C1-6 alkyl or sulphonate, R3 is O, S, hydroxyl,
mercapto or amino, R4 is H, hydroxyl, methyl, cyano, nitro, halogen
such as Br, R5 is H or Br X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are
independently O'' or S'', Y is O, imido, methylene or
dihalomethylene, such as difluoromethylene, Z is CH.sub.2, n and m
are independently 0 or 1, and n+m is 0, 1 or 2, A is H or ribose,
linked at the 5 position with a pyrimidine or purine residue or
pyrimidine or purine derivative selected from the group of uracil,
cytosine, guanine, adenine, xanthine, hypoxanthine, linked through
the 1 or 9 position, respectively or ribose linked at the 5
position with a pyrimidine residue having formula II
##STR00005##
wherein the denoted R groups are as listed above or ribose lined at
the 5 position with a purine residue having formula (III)
##STR00006##
wherein R6 is NH2, while R7 is nothing and there is a double bond
between N1 and C6 (adenine) or wherein R6 is NH2 and R7 is O and
there is a double bound between N1 and C6 (adenine-1-oxide) or
wherein R6 and R7 together form a ring of --NCH.dbd.CH-- from N6 to
N1 with a double bound between N-6 and C6 (1,
N.sup.6-ethenoadenine),
[0117] In a further embodiment, the compound used is
P.sup.1-(uridine 5')-P.sup.4-(2'-deoxycytidine 5')tetraphosphate or
a salt thereof, such as a tetrasodium salt (INS37217).
[0118] In yet further embodiments, the compound capable of
stimulating the P2Y2 receptor is one of the compounds described in
U.S. Pat. No. 5,292,498 (paragraph 2, line 1 to line 32) and U.S.
Pat. No. 5,789,391 (paragraph 2, line 40 to paragraph 3, line 55).
In yet another embodiment, the compound used is a P2Y2 agonist
described in U.S. Pat. No. 5,837,861, such as P1,P4-Di(uridine
5'-P2,P3-methylene tetraphosphate), P1,P4-Di(uridine
5'-P2,P3-difluoromethylenetetraphosphate), P1.P4-Di(uridune
5'-P2,P3-imidotetraphosphate), P1,P4-Di(4-thioruridine
5'-tetraphosphate), P1,P5-Di(uridine 5'-pentaphosphate), and
P1,P4-Di(3,N.sup.4-ethenocytidine 5'-tetraphosphate).
[0119] UTP, a derivative thereof, or a salt thereof, may be
formulated as a free base or salt. Pharmaceutically acceptable
salts include acid addition salts (formed with the free amino
groups of the peptide compound) and which are formed with inorganic
acids such as, for example, hydrochloric or phosphoric acids, or
such organic acids as acetic acid, oxalic acid, tartaric acid,
mandelic acid, and the like. Salts formed with the free carboxyl
group may also be derived from inorganic bases such as, for
example, sodium, potassium, ammonium, calcium, or ferric
hydroxides, and such organic bases as isopropylamine,
trimethylamine, 2-ethylamino ethanol, histidine, procaine, and the
like.
[0120] Preferred salts of UTP, a derivative thereof, or a salt
thereof, are alkali salts or alkali earth salts, such as sodium
salts, potassium salts, calcium salts and magnesium salts. Other
preferred salts include, but are not limited, to tris salts,
hydrates and dihydrates. The UTP salt may comprise one or more of
the above mentioned salts on any UTP residue, such as disalts,
trisalts and tetrasalts, for example disodium salts, dipotassium
salts, dicalcium salts and dimagnesium salts, as well as trisodium
salts, tripotassium salts, tricalcium salts and trimagnesium salts
and tetrasodium salts, tetrapotassium salts, tetracalcium salts and
tetramagnesium salts. The UTP salts may be substituted on any UTP
residue, preferably the salts are 5' or C' substituted.
Formulations and Modes of Administration
[0121] UTP, a derivative thereof, or a salt thereof may be
delivered in any suitable way known in the art. Preferred modes of
delivery include parenteral, intravenous, intra-arterial, in situ
infusion, and the like.
[0122] UTP, a derivative thereof or a salt thereof may be
formulated for parenteral administration (e.g., by injection, for
example bolus injection or continuous infusion) and may be
presented in unit dose form in ampoules, pre-filled syringes, small
volume infusion or in multi-dose containers with an added
preservative. A diagnostic composition for parenteral
administration may include sterile aqueous and non-aqueous
injectable solutions, dispersions, suspensions or emulsions in oily
or aqueous vehicles, for example solutions in aqueous polyethylene
glycol, as well as sterile powders or lyophilisates to be
reconstituted in sterile injectable solutions or dispersions prior
to use.
[0123] UTP, a derivative thereof, or a salt thereof, may be in
powder form, obtained by aseptic isolation of sterile solid or by
lyophilisation from solution for constitution before use with a
suitable vehicle, e.g., sterile, pyrogen-free water. Aqueous
solutions should be suitably buffered if necessary, and the liquid
diluent first rendered isotonic (i.e., to an osmolarity of about
300 mOsm) with sufficient saline or glucose. Solubility of UTP, a
derivative thereof, or a salt thereof increases by warming and
lowering the pH of the aqueous solution. The resulting aqueous
solution can be sterilized by filtration. The aqueous solutions can
also be heated to a sterilization temperature, e.g., 99.degree. C.
for 10 min at physiological pH values, e.g., in order to inactivate
enzymes such as ectonucleotidases and ectophosphatases, without
degradation of the nucleotides. The aqueous solutions are
particularly suitable for in situ infusion, and intravenous,
intramuscular, subcutaneous and intraperitoneal delivery. The
sterile aqueous media employed are all readily available by
standard techniques known to those skilled in the art. The reagent
and vehicle, of course, can be provided in ready-to-use
(pre-sterilized) form after reconstitution at the use point.
[0124] Solutions of compounds or pharmaceutically acceptable salts
thereof can be prepared in water or saline, and optionally mixed
with a nontoxic surfactant. Compositions for in situ infusion, or
intravenous or intra-arterial delivery may include sterile aqueous
solutions that may also contain buffers, liposomes, diluents and
other suitable additives.
[0125] The compounds of the present invention may be administered
parenterally in a sterile medium. The compound, depending on the
vehicle and concentration used, can either be suspended or
dissolved in the vehicle. Advantageously, adjuvants such as local
anesthetics, preservatives and buffering agents can be dissolved in
the vehicle including UTP degradation enzyme blockers. The sterile
injectable preparation may be a sterile injectable solution or
suspension in a non-toxic parentally acceptable diluents or
solvent. Among the acceptable vehicles and solvents that may be
employed are physiological saline, sterile water or Ringer's
solution.
[0126] The parenteral compositions can be presented in unit-dose or
multi-dose sealed containers, such as ampules and vials, and can be
stored in a freeze-dried (lyophilized) condition requiring only the
addition of the sterile liquid excipient, for example, water, for
injections, immediately prior to use. Extemporaneous injection
solutions and suspensions can be prepared from sterile powders,
granules, and tablets of the kind previously described.
[0127] The dosage forms suitable for injection or infusion can
include sterile aqueous solutions comprising the active ingredient.
In all cases, the ultimate dosage form must be sterile, fluid and
stable under the conditions of manufacture and storage.
[0128] Sterile injectable solutions can be prepared by
incorporating the compound(s) or pharmaceutically acceptable
salt(s) thereof in the required amount in the appropriate solvent
with various of the other ingredients enumerated above, as
required, followed by filter sterilization.
[0129] In preferred embodiments, UTP, a derivative thereof or a
salt thereof, is formulated in liquid form for delivery via
continuous intravenous infusion, in situ infusion, intracoronary
infusion, drip infusion, intracoronary bolus injection, a guiding
catheter, or an IC micro-catheter. In other preferred embodiments,
UTP, a derivative thereof, or a salt thereof, is formulated in
liquid form for administration intravenously in legs for the
determination of blood flow in the legs. UTP, a derivative thereof,
or a salt thereof, can also be formulated in liquid form for
delivery to the kidneys or via intracoronary infusion to the heart
for the determination of blood flow.
[0130] Other suitable embodiments relate to a diagnostic
composition comprising UTP, a derivative thereof, or a salt
thereof, in a pharmaceutically acceptable aqueous carrier suitable
for administration into a human patient, said composition
containing said compound in the range of 10 to 1000 .mu.mol/ml,
preferably in the range of 50 to 400 .mu.mol/ml, more preferably in
the range of 100 to 360 .mu.mol/ml. Examples of such compositions
include:
Composition I: The concentration of UTP, a derivative thereof, or a
salt thereof in the injectable composition can be between 10-2000
.mu.g/ml, with a preferred diagnostic concentration between 20-500
.mu.g/ml for IC use and 50-2000 .mu.g/ml for iv use. Composition
II: The concentration of UTP, a derivative thereof, or a salt
thereof can be controlled by adding sterile aqueous solution to dry
powder UTPtrissalt or UTPNa.sub.3 by techniques know to those
skilled in the art to bring the concentration to about 100 .mu.g/ml
for IC and 300 .mu.g/ml for iv use, the limit of its solubility
under ambient conditions. Composition 3: The concentration of UTP,
a derivative thereof, or a salt thereof can be, in a clinical dose
range, 10-1000 .mu.g/ml, with preferred ranges of 25-500 .mu.g/ml,
20-100 .mu.g/ml, 40-150 .mu.g/ml, 60-160 .mu.g/ml, 80-360 .mu.g/ml,
100-240 .mu.g/ml, 120-480 .mu.g/ml, and 150-600 .mu.g/ml.
[0131] A related embodiment relates to a diagnostic composition
wherein UTP, a derivative thereof, or a salt thereof, is in
isotonic saline.
[0132] The rate of intravascular infusion of UTP, a derivative
thereof, or a salt thereof, in increasing order of preference, is
about 20 .mu.g to about 2000 .mu.g per minute, about 50 .mu.g to
about 600 .mu.g, about 80 .mu.g to about 360 .mu.g, about 100 .mu.g
to about 500 .mu.g, about 150 .mu.g to about 400 .mu.g, about 180
.mu.g to about 360 .mu.g, about 240 .mu.g to about 360 .mu.g, and
about 180 .mu.g to about 240 .mu.g per minute.
[0133] UTP can be delivered by intracoronary infusion continually
or by bolus via a guiding, FFR/thermodilution catheter or
microinfusion catheter by stepwise dose escalation starting at 20
.mu.g/min to induce maximal coronary blood flow, which corresponds
to minimal distal coronary pressure. When steady-state hyperemia is
achieved, preferably with continuous infusion (i.e., no further
decrease in P.sub.d is occurring), FFR can be calculated as the
ratio of the mean distal intracoronary pressure measured by the
pressure wire to the mean arterial pressure measured by the
coronary catheter. As such, a stepwise dose escalation from 20
.mu.g/min to about 400 .mu.g/min during continuous UTP infusion in
any given assessed coronary artery should render the lowest
possible P.sub.d and therefore the most accurate FFR value. Thus,
hyperemic stimuli can be given as follows: an IC continuous
infusion of UTP, a derivative thereof, or a salt thereof in
incremental doses of 10, 20, 40, 80, 160, 240, 360 and 400
.mu.g/min, in both the left and right coronary artery depending on
lesion anatomy.
[0134] When UTP, a derivative thereof, or a salt thereof is
administered via continuous intracoronary infusion, the rate of
infusion maybe about 5 .mu.g to about 600 .mu.g/min, about 10 .mu.g
to about 550 .mu.g/min, about 20 .mu.g to about 500 .mu.g/min,
about 30 .mu.g to about 450 .mu.g/min, about 50 .mu.g to about 400
.mu.g/min, about 60 .mu.g to about 360 .mu.g/min, about 80 .mu.g to
about 360 .mu.g/min, and about 180 .mu.g to about 360
.mu.g/min.
[0135] In terms of the solution to be infused, the UTP
concentration can vary. Typically, the concentration will be from
about 50 to about 100 .mu.g/ml to be administered at a rate of 1-5
ml/min for about 3 to 5 minutes. Thus, a vial of pre-made solution
of UTP should conveniently contain at least 10 ml of solution and
could contain up to 25 ml. Larger amounts are possible but
unnecessary for individual use.
[0136] If UTP is provided in solid form (e.g., lyophilized) in a
vial it can be provided in individual use amounts according to the
foregoing guidelines or in bulk and then dissolved prior to use in
an appropriate amount of aqueous solvent.
[0137] The amounts given herein apply, on a UTP basis, to UTP salts
and derivatives, but may need to be adjusted to account for
differences in potency.
[0138] A typical practice is as follows: UTP solutions are freshly
prepared from sterile lyophilized powder (2-mL ampoules containing
20 mg UTP as tris salt or trisodium salt) and then diluted
appropriately in aqueous NaCl 0.9%. The solution can then be passed
through a 0.2-microm Millipore filter is in a concentration of 50
microgram/ml which can then be pushed by an infusion rate of 1-5
ml/min in order to give a concentration of 50 to 250 microgram/min.
If higher concentrations are needed to produce an even lower FFR
the infusion rate can be increased even further, if for instance
the patient has some of the known P2Y2 receptor polymorphisms (see,
e.g., Janssens, R. et al, "Human P2Y2 receptor polymorphism:
identification and pharmacological characterization of two allelic
variants" Br J. Pharmacol. 1999 June; 127(3):709-16; and Buescher,
R. et al, "P2Y2 receptor polymorphisms and haplotypes in cystic
fibrosis and their impact on Ca2+ influx"Pharmacoaenet Genomics.
2006 March; 16(3):199-205).
[0139] The drug may be administered at any time when the patient is
in need of a hyperemic assessment such as FFR or other related
diagnostic procedures, such as another form of nuclear imaging
(including MPI), Ultrasound and echo cardiography, Fractional flow
reserve, MRI/MRA, CT scan, PET scan, and ankle brachial index using
mean arterial pressure.
Methods for Assessing Compromised Blood Flow
[0140] Methods of assessing compromised blood flow include nuclear
imaging such as MPI, ultrasound and echo cardiography, fractional
flow reserve, MRI/MRA, CT scan, PET scan, and ankle brachial index
using mean arterial pressure. Compromised blood flow means any
alteration in blood flow compared to normal blood flow, for
example, an alteration caused by a stenosis or blood clot.
Conversely, normal blood flow means blood flow that is
uncompromised by, for example, a stenosis or a blood clot. A
reference for normal blood flow may, for example, be developed by
measuring the blood flow in at least 20 individuals with no
suspected illnesses and determining the average. Conversely, some
measurements are specific to the individual, e.g., FFR
measurements. That is, the FFR value is solely dependent on the
individual's ability to increase blood flow compared to when at
rest.
[0141] In other contexts, a "reference value" may represent the
value of blood flow associated with an abnormal condition. For
example, when FFR is used to assess blood flow, the measured value
is pressure differential between the distal end of a stenotic blood
vessel segment under conditions of maximal hyperemia and the
reference value is the corresponding pressure differential under
similarly hyperemic conditions in the same vessel without stenosis.
The connotation of "reference value" as used in a specific context
will be apparent to one of ordinary skill in the art.
[0142] To determine whether a blood vessel has compromised blood
flow, the blood flow can be assessed quantitatively by obtaining a
value that correlates to blood flow in the vessel. This obtained
value can then be compared to a reference value, which can be
obtained, for example, from a similar blood vessel in the
individual. It can then be determined whether the individual has a
compromised blood flow based on the results of the comparison. This
comparison allows for the determination of compromised blood flow
in a blood vessel and may thereby assist in determining the
presence of a stenosis and/or in diagnosing a disease or disorder,
for example, Peripheral Artery Disease (PAD), coronary
atherosclerosis, renal artery disease, atherosclerosis and/or
ischemic heart disease.
[0143] The similar blood vessel may be any vessel with the same
cross section area +/-20%. The similar vessel may thus, for
example, be a similar blood vessel in the same individual, such as
a vessel in same individual with the same cross section area
+/-20%, and which has the same distance to the heart +/-20%. For
example, if the blood vessel with suspected compromised blood flow
is on the left side of the body, the similar vessel may be the
corresponding vessel on the right side of the body. The similar
vessel can, however, also be the same vessel in another healthy
individual.
[0144] When blood flow is measured in the legs, the similar blood
vessel with normal blood flow may be the vessel in one leg of an
individual, wherein the vessel with a suspected compromised blood
flow is in the other leg. When blood is measured in the heart, the
similar blood vessel with normal blood flow may be one coronary
artery in an individual, wherein the blood vessel with a suspected
compromised blood flow is in another coronary artery.
[0145] Blood flow in the present invention can be assessed by any
appropriate method known in the art. For example, blood flow can be
assessed by fractional flow reserve (FFR) measurement, coronary
flow reserve (CFR) measurement, mean arterial pressure (MAP)
measurement, and arterial peak velocity (APV) measurement.
[0146] FFR was originally used in coronary catheterization to
measure pressure differences across a coronary artery stenosis to
determine the likelihood that the stenosis impedes oxygen delivery
to the heart muscle, and is defined as the pressure behind (distal
to) a putative stenosis relative to the pressure before the
putative stenosis. The result is an absolute number; an FFR of 0.50
means that a given stenosis causes a 50% drop in blood pressure
across the stenotic area. That is, FFR expresses the maximal flow
down a vessel in the presence of a stenosis compared to the maximal
flow in the hypothetical absence of the stenosis. During coronary
catheterization, a catheter is inserted into the femoral (groin) or
radial arteries (wrist) using a sheath and guidewire. FFR uses a
small sensor on the tip of the wire (commonly a transducer) to
measure pressure, temperature and flow to determine the exact
severity of the lesion. This is done during maximal blood flow
(hyperemia). A pullback of the pressure wire is performed, and
pressures are recorded across the vessel.
[0147] FFR measurements can be carried out in any blood vessel in
the body, for example, those in the legs, kidney, or heart. Any
variation to the FFR method is contemplated to be within the scope
of the present invention. In specific embodiments, the FFR method
uses a guidewire or the tip of an IC microcatheter (Progreat
Microcatheter System, Terumo, Japan).
[0148] Other catheters suitable for use in conjunction with the
invention are disclosed in U.S. Provisional application Ser. No.
61/357,857, which is hereby incorporated by reference.
[0149] Advantages of using UTP over adenosine compounds in FFR
include: the instantaneous achievement of steady state by UTP,
making it feasible to perform accurate measurements and the
pullback maneuver and bringing FFR procedure time down; the more
accurate estimation of coronary blood flow, resulting in a more
precise FFR because UTP produces close to maximum perfusion; UTP is
not associated with side effects; UTP allows for a clear dose
response curve, and UTP is short-acting, with no long-term effects.
There is also emphasis on procedure-related complications and this
new method therefore allows for repeated and easy measurement of
FFR and can be performed via the radial artery on an outpatient
basis, whereas intravenous adenosine will always require central
venous access.
[0150] MAP is the perfusion pressure seen by organs in the body.
Compromised blood flow may, in the order of preference, be
reflected in a MAP of less than 60 mmHg, less than 50 mmHg, less
than 40 mmHg, less than 30 mmHg, or less than 20 mmHg.
[0151] Average peak velocity (APV) may also be used in the present
invention to determine the suspected compromised blood flow. APV in
the range of 5 to 30 msec.sup.-1 is indicative of compromised blood
flow. Thus, in order of preference, APV of less than 30
msec.sup.-1, preferably less than 20 msec.sup.-1, and more
preferably less than 10 msec.sup.-1 are considered indicative of
compromised blood flow.
[0152] Other methods include stress tests, such as exercise, stress
echocardiogram (e.g., dobutamine stress echocardiogram), myocardial
scintigraphy/myocardial perfusion imaging (MPI), and the like
[28-31].
[0153] Contraindications to dobutamine include: chest pain, high
blood pressure, dizziness, nausea and extreme fatigue, ingestion of
caffeine and treatment with beta blockers. Given that current risks
of the stress echocardiogram procedure with dobutamine are not seen
with UTP, dobutamine can be substituted with UTP, a derivative
thereof, or a salt thereof in stress echocardiograms to assess
blood flow in an blood vessel, to assess the heart's function and
structures such as valve stenosis, to determine limits for safe
exercise in patients who are entering a cardiac rehabilitation
program and/or those who are recovering from a cardiac event, such
as a heart attack (myocardial infarction, or MI) or heart surgery,
to evaluate blood pressure during stress testing, to assess stress
or exercise tolerance in patients with known or suspected coronary
artery disease or to evaluate the cardiac status of a patient about
to undergo surgery with for instance aortic stenosis.
[0154] MPI is the most widely used non-invasive method used for the
detection of coronary artery disease, risk assessment, detection of
viable myocardium, and evaluation of the effects of various
therapeutic interventions. Adenosine and dipyridamole have been the
mainstays of vasodilator stress testing. Dobutamine stress MPI is,
reserved for patients with contraindications for vasodilator
testing with adenosine. However, all adenosine receptor agonists,
including regadenoson, have been associated with
bronchoconstriction, angina, severe hypotension and sinoatrial and
atrioventricular nodal block because adenosine receptor agonists
can depress the SA and AV nodes and may thus cause first-, second-
or third-degree AV block, or sinus bradycardia; thus the drugs
should not be given to patients with 2nd or 3rd degree AV block, or
sinus node dysfunction. Importantly, UTP has none of these
disadvantages, being more receptor selective and closer to maximal
coronary blood flow and as there are no "adenine" effects of the
current compound as it acts through a completely different
purinergic receptor system (P2Y2). It is therefore much safer to
use systemically because of limitation to systolic and diastolic
blood pressure drops+no effect on the AV node. As such, UTP, a
derivative thereof, or a salt thereof can be used in place of
adenosine receptor agonists in MPI.
Methods for Detecting Blood Flow
[0155] Compromised blood flow may be determined with any device in
the art useful for this purpose, such as a sphygmomanometer, blood
pressure meter, and the like. Compromised blood flow may also be
determined using techniques in the art useful for this purpose,
such as the Color Doppler technique, Pulsed Doppler, Power Doppler,
Doppler ultrasound, thermodilution, echo cardiography,
plethysmography, and the like. Other methods suitable for use in
the present invention include cardiac magnetic resonance imaging
(MRI), computed tomography (CT) scan, cardiac catheterization,
chest CT, myocardial perfusion scan, radionucleotide angiography,
ultrafast CT scan, and the like.
[0156] Blood flow can also be monitored from an external position
on the vessel by using, for example, a flow probe.
[0157] Methods for detecting blood flow can be combined with
methods for assessing blood flow presented above.
Kit-of-Parts
[0158] All the materials and reagents required to determine the
blood flow in an artery or vein of an individual with suspected
compromised blood flow according to the present invention can be
assembled together in a kit, such kit includes at least UTP, a
derivative thereof, or a salt thereof as an active diagnostic
ingredient, and instructions for the use thereof in an individual
with suspected compromised blood flow according to any of the
methods described herein.
[0159] In the above test kit, the reagents may be supplied from
storage bottles or one or more of the test tubes may be prefilled
with the reagents or controls.
[0160] The components of the kit, particularly UTP, a derivative
thereof, or a salt thereof, may be provided in dried or lyophilized
forms. When reagents or components are provided as a dried form,
reconstitution generally is by the addition of a suitable solvent.
It is envisioned that the solvent also may be provided in another
container means. Alternatively, UTP, a derivative thereof, or a
salt thereof can be provided in ready-to-use (pre-sterilized) form
after reconstitution at the use point. The UTP, a derivative
thereof, or a salt thereof can also be provided in suspended form,
i.e., already suspended in the suitable solvent.
[0161] The kits of the present invention also will typically
include a means for containing the reagents such as vials or tubes
in close confinement for commercial sale such as, e.g., injection
or blow-molded plastic containers into which the desired vials are
retained.
[0162] The kits will also comprise a set of instructions on how to
determine suspected compromised blood flow according the methods of
the invention.
[0163] Different kits are provided with components, reagents and
instructions suitable for the preferred modes of delivery described
herein above, including delivery via continuous intravenous
infusion, in situ infusion, intracoronary infusion, drip infusion,
intracoronary bolus injection, a guiding catheter, or an IC micro
catheter. Guiding catheter(s) and/or microcatheter(s) may also be
provided with the kits.
[0164] Examples of suitable commercially available catheters for
use with the kits are: ComboWire.RTM. and FloWire.RTM. Doppler
Guide Wire (Volcano Corporation); PressureWire.TM. Certus and
PressureWire.TM. Aeris Wireless (St. Jude Medical, Inc.).
EXAMPLES
Example 1
Systemic Infusion of UTP for Myocardial Perfusion Imaging
(Prophetic)
[0165] MPI is a form of functional cardiac imaging that may be used
for the diagnosis of ischemic heart disease. The underlying
principle is that under conditions of stress, diseased myocardium
receives less blood flow than normal myocardium. MPI is one of
several types of cardiac stress tests.
[0166] A cardiac specific radiopharmaceutical, such as
.sup.99mTc-tetrofosmin (Myoview, GE healthcare) or
.sup.99mTc-sestamibi (Cardiolite, Bristol-Myers Squibb) is
administered. Following this, the heart rate and coronary blood
flow is raised to induce myocardial stress by systemic infusion of
UTP, a derivative thereof, or a salt thereof.
[0167] SPECT imaging performed after stress reveals the
distribution of the radiopharmaceutical, and therefore the relative
blood flow to the different regions of the myocardium. Diagnosis is
made by comparing stress images to a further set of images obtained
at rest (the reference value). As the radionuclide redistributes
slowly, it is not usually possible to perform both sets of images
on the same day, hence a second attendance is required 1-7 days
later. However, if stress imaging is normal, it is unnecessary to
perform rest imaging, as it too will be normal--thus stress imaging
only is normally performed.
[0168] MPI has been demonstrated to have an overall accuracy of
about 83% (sensitivity: 85%; specificity: 72%) and is comparable
with (or better than) other non-invasive tests for ischemic heart
disease.
Example 2
Local Infusion of UTP Via Guiding Catheter in the Coronary Arteries
in Humans with Coronary Artery Disease
[0169] The study was performed in 23 patients undergoing elective
coronary arteriography (CAG) due to repetitive episodes of typical
ischemic chest pain or in patients with recent Non-ST Elevated
Myocardial Infarction (>2 days from entry into study). In
eligible patients with uni- or multivessel coronary artery disease,
lesions with stenosis of at least 50% of their diameter and that
were thought to require PCI on the basis of angiographic appearance
and clinical data were identified.
Dose/Response Protocol
[0170] In the first part of the experiment, FFR and Coronary Flow
(velocity, CFR) were measured after the induction of coronary
hyperemia by a continuous intracoronary infusion of UTP (Jena
Bioscience GmbH, Germany) and adenosine in random order in a guide
catheter (5F catheter, Cordis Corp.). Two UTP doses of 240 and 360
.mu.g/min were tested. UTP was prepared by dissolving 100 mg of UTP
trisalt (Sigma Aldrich) in 50 ml isotonic NaCl. Of this 50 ml
solution, 40 ml was filter sterilized and added to sterile NaCl
solution to a final volume of 500 ml, providing a 0.16 mg/ml
concentration. 8-10 50 ml syringes of this solution can be prepared
(2 syringes per FFR study). 3 ml/min=480 .mu.g/min=0.9 .mu.mol/min.
Subjects thus received either 1.5 ml/min of UTP infusion or 2.25
ml/min of UTP infusion for a total of 3 minutes each. Patients also
received adenosine (Sigma Aldrich) in the same eqipotent
concentration.
[0171] All measurements were performed on at least 2 separate
occasions to achieve a reproducible result with a mean value
calculated. After each measurement, care was taken that APV
returned to baseline before the administration of the next dose.
For all measurements using both drugs and both routes of
administration, changes in heart rate, blood pressure, and ECG were
recorded.
[0172] In the second part of the experiment, a full dose response
curve was generated for a gradual incremental increase in
continuous UTP infusion while both CFR and FFR were measured
simultaneously prior to percutaneous coronary intervention (PCI).
Hyperemia was induced at 80 .mu.g/min of continuous intracoronary
UTP and adenosine, and the flow reserve values were compared (Table
1).
[0173] In the third part of the experiment, both CFR and FFR were
measured simultaneously after percutaneous coronary intervention
(PCI). Hyperemia was induced by either 240 or 360 .mu.g/min of
continuous intracoronary UTP and equipotent adenosine, and the flow
reserve values were in some patients compared with the hyperemic
response of a complete, proximal coronary occlusion for 30 s.
Calculations of Fractional and Coronary Flow Reserve
[0174] FFR is defined as the ratio of hyperemic flow in a stenotic
artery to the hyperemic flow in the same artery if there was no
stenosis present. FFR therefore expresses maximum hyperemic blood
flow in a stenotic vessel as a fraction of its normal value. FFR
can be calculated from intracoronary pressure measurements obtained
during maximal hyperemia by the following equation:
FFR=P.sub.d-P.sub.v/P.sub.a-P.sub.v.fwdarw.P.sub.d/P.sub.a, where
P.sub.a is the mean proximal coronary pressure (mean aortic
pressure), P.sub.d is the mean distal coronary pressure, and
P.sub.v is the mean central venous pressure. The coronary flow
(velocity) reserve is the ratio of maximum to baseline hyperemic
coronary flow velocity and is used as a surrogate for CFR. Using
the Volcano Combomap.RTM., APV throughout the cardiac phase was
measured and CFR calculated from
APV.sub.(hyperemia)/APV.sub.(basal).
Results
[0175] The results of this experiment are shown in FIGS. 1-4 and
8.
[0176] Comparison of IC adenosine and IC UTP continuous adenosine
infusion in a dose response curve of six patients:
TABLE-US-00001 TABLE 1 FFR BL ADO ADO ADO ADO ADO BL UTP UTP UTP
UTP UTP Patient ado 80 160 240 320 400 UTP 80 160 240 320 400 1.00
0.98 0.87 1.02 1.01 1.01 0.89 0.90 0.90 2.00 0.91 0.96 0.91 0.89
0.89 0.92 0.90 0.89 0.89 0.92 3.00 0.88 0.88 0.75 0.71 0.70 0.88
0.73 0.73 0.73 0.72 4.00 0.87 0.83 0.80 0.81 0.79 0.85 0.79 0.79
0.79 0.77 5.00 0.97 0.95 0.95 0.94 0.96 1.01 0.88 0.86 0.87 0.86
6.00 0.79 0.76 0.60 0.60 0.54 0.56 0.78 0.56 0.56 0.55 0.56 0.56
Mean 0.90 0.86 0.81 0.81 0.82 0.82 0.91 0.74 0.77 0.79 0.78 0.79
2SEM 0.06 0.08 0.13 0.11 0.14 0.27 0.07 0.13 0.12 0.11 0.11
0.23
[0177] It is clear that at any given level of continuous UTP
infusion, the FFR value is lower in comparison to the same
equipotent level of adenosine. The lowest FFR level using adenosine
is 0.81.+-.0.11, however the lowest level for UTP is 0.74.+-.0.13;
(P<0.05). As stated, the doses of adenosine and UTP are
different numerically because the preparations have been made to be
equipotent.
[0178] The times to induction of maximal hyperemia in all IC
continuous UTP infusion rates were shorter than that of IC
continuous adenosine infusion. As shown in all 23 patients, FFR was
significantly decreased with IC 240 .mu.g/min infusion of UTP in
comparison to adenosine infusion (p=0.003) (FIG. 1). Consistent
with this, P.sub.d, or mean distal coronary pressure, was also
significantly decreased with UTP infusion compared to adenosine
infusion.
[0179] It has previously been shown that IC continuous adenosine
infusion is more effective in inducing maximal coronary hyperemia
than IV continuous adenosine infusion [8]. Particularly early
induction of optimal coronary hyperemia has a great advantage in
repetitive measurement of FFR. However, in comparison to UTP,
adenosine is not as vasodilatatorily potent presumably due to
differences in activated receptor types, affinity for the
respective receptors, and amounts infused. Thus, although the IC
adenosine continuous infusion method for FFR measurement is an
accepted standard method for inducing maximal and steady-state
coronary hyperemia, it does not induce maximal hyperemia when
compared with UTP administration.
[0180] None of the UTP-treated patients in the current trial had
chest pain, dyspnea, second or 3 degree A-V block or changes in
systemic blood pressure and heart rate during IC continuous UTP
infusion, whereas most patients felt uncomfortable chest pain and 2
patients had 3 degree A-V block during adenosine infusion. Our IC
UTP infusion method is thus safe for inducing coronary hyperemia
without any systemic complications compared to the IC and IV
adenosine infusion method.
[0181] The optimal dose of UTP for achieving maximal coronary
hyperemia by our guide catheter method was UTP in concentrations of
80-400 .mu.g/min. Intracoronary UTP infusion at these doses can
induce more rapid and more potent coronary hyperemia than previous
methods compared with equipotent IC adenosine doses which are more
potent than the standard IV adenosine concentration of 140
.mu.g/min. No further decrease in FFR was observed after IC UTP
infusion at >360 .mu.g/min.
[0182] We conducted this study in most patients where FFRs were
present in the gray zone between 0.76 and 0.80 assessed by IC bolus
adenosine injection, but where IC infusion of UTP lowered the FFR
even further due to bigger post stenotic vasodilatation. The
preferred infusion rate for inducing maximal hyperemia by the IC
continuous UTP infusion method is thus .about.80 to 400
.mu.g/min.
[0183] The results collectively demonstrate that IC continuous
infusion of UTP is safe and useful for inducing optimal coronary
hyperemia without any additional procedure; IC UTP infusion is a
more potent vasodilatator than IC adenosine infusion in equipotent
concentrations; while previous studies have shown that IC Ado=IC
ATP infusion>IV adenosine infusion, the findings of the present
study suggest that UTP>adenosine=ATP; and IC UTP infusion is not
associated with adverse effects in contrast to IC or IV adenosine
or ATP infusion.
Example 3
Local Infusion of UTP Via a Microcatheter in the Coronary Arteries
in Humans with Coronary Artery Disease
[0184] As described previously, inducing stable maximal coronary
hyperemia is essential for measurement of fractional flow reserve
(FFR). This second experiment in a similar patient group evaluated
the differential efficacy of intracoronary (IC) continuous
adenosine infusion vs. IC continuous uridine triphosphate (UTP)
infusion via a microcatheter for inducing steady state maximal
coronary hyperemia. The present study was designed to evaluate the
safety and effectiveness of the equimolar concentrations of UTP vs.
adenosine infusion for use in the FFR method. Time to achievement
of steady-state, impact of maximal hyperemia (lowest FFR) for the
different compounds and side effects were recorded in 10 patients
with intermediate coronary lesions. FFR was measured consecutively
by IC continuous adenosine or UTP infusion using a microcatheter to
bypass the proximal pressure transducer. The IC microcatheter
(Progreat Microcatheter System, Terumo, Japan) used was positioned
at the coronary ostium, and FFR was then measured by increasing IC
continuous adenosine or UTP infusion rates in equimolar
concentrations from 10 to 400 .mu.g/min via the microcatheter.
[0185] After femoral catheterization, coronary angiography was
performed with the standard femoral approach. Heparin was
administered according to standard procedures.
[0186] Intracoronary nitroglycerin (0.2-0.3 mg) was administered
before the control angiograms were made in the microcatheter study.
Heart rate and arterial pressure were continuously monitored
throughout the procedure. After a guiding catheter (5F catheter,
Cordis Corp.) without side holes was positioned at the coronary
ostium, coronary angiograms were obtained from multiple
projections. Quantitative coronary analysis was performed by using
an independent analyzer blinded to the results of FFR using a
computer-assisted, automated computerized edge-detection algorithm
(Siemens Medical System). The external diameter of the
contrast-filled catheter was used as a calibration standard.
Minimal luminal diameter, vessel diameter of the reference segment,
and the percent diameter stenosis at end diastole were measured
from the worst-view trace. After coronary angiography, a 0.014-in.
pressure wire (Combowire, Volcano Corporation, US) was advanced
distally to the stenosis through a 6F guiding catheter. In the
microcatheter study, an IC bolus injection of nitroglycerin
(0.2-0.3 mg) was given before advancing the pressure wire through
the stenosis in order to avoid any mechanically-induced coronary
vasoconstriction. The pressure wire was externally calibrated and
then advanced to the distal tip of the catheter. It was verified
whether equal pressure was recorded at both the catheter and the
pressure wire. The pressure wire was advanced through the coronary
catheter, introduced into the coronary artery, and positioned
distal to the stenosis.
[0187] Distal coronary pressure (P.sub.d) and proximal coronary
pressure (P.sub.a) were measured at baseline and at maximal
hyperemia (adenosine vs. UTP) simultaneously. Fractional flow
reserve was calculated by dividing mean P.sub.d by mean P.sub.a
during maximal hyperemia. The time to optimal vasodilatation (time
needed to reach>90% of the minimal value of P.sub.d/P.sub.a
after administration of the adenosine or UTP) was computed in order
to assess whether procedure time was prolonged. The hyperemic
stimuli were given as follows: an IC continuous infusion of
adenosine or UTP in incremental doses of 10, 20, 40, 80, 160, 240,
360 and 400 .mu.g/min, in both the left and right coronary artery
depending upon lesion anatomy. The dosages were increased stepwise
by IC continuous infusion with the microcatheter where the stepwise
dose increase was recorded continuously without breaks. After each
stepwise increase, FFR and CFR were recorded automatically. The
next hyperemic stimulus UTP vs adenosine was given when P.sub.a,
P.sub.d, and heart rate returned to their baseline values.
[0188] As described above, the results showed that the fractional
flow reserve measured by the IC continuous UTP infusion method was
significantly lower than that of the IC continuous adenosine
infusion method. Also, induction time to optimal coronary hyperemia
by our method was also shorter than that by the IC continuous
adenosine infusion method. As stated above, the induction of
optimal coronary hyperemia has a great advantage in repetitive
measurement of FFR and our method makes it possible to measure FFR
repetitively and easily within a short period of time when compared
with previous methods. None of the patients had chest pain in the
UTP group but nearly all felt angina in the adenosine group due to
P1 pain receptor stimulation. Also, some patients had a transient
second degree A-V block during IC adenosine infusion. There was no
difference in systemic blood pressure and heart rate during IC
continuous UTP or adenosine infusion. The IC UTP infusion method is
thus safe for inducing coronary hyperemia without any systemic
complications compared to the IC adenosine infusion method.
[0189] The optimal dose of UTP for achieving maximal coronary
hyperemia and thereby the lowest FFR by the UTP method was
approximately 80 .mu.g/min for UTP and 240 .mu.g/min for adenosine
(FIG. 5). However, no intracoronary adenosine infusion produced as
low FFR levels at any given concentration as that achieved during
UTP infusion, meaning that adenosine, even at its highest
concentration, rendered a higher FFR than UTP. UTP above 80
.mu.g/min did not further lower FFR, and must thus be assumed to be
the correct amount to be infused. However, given that some patients
may be more or less responsive to this dose depending upon their
number of effective receptors and distribution, it is recommended
that the starting dose should be around 50 .mu.g/min and then
increased incrementally until the lowest level of FFR is achieved.
In this manner, the dose range can be individualized according to
any given patient's need for an optimal diagnosis.
[0190] All patients tolerated UTP without side effects, but nearly
all patients experienced side effects during the adenosine
procedures. FFRs measured by UTP infusion were significantly lower
than those by IC adenosine infusion (P<0.05). Intracoronary UTP
infusion was also able to shorten the time to induction of optimal
and steady-stable hyperemia which also lasted slightly longer
(.about.20 seconds) with UTP compared to adenosine infusion.
TABLE-US-00002 FFR BL ADO ADO ADO ADO ADO ADO ADO ADO Patient ado
10 20 40 80 160 240 320 400 1.00 0.98 0.87 1.02 1.01 2.00 0.91 0.96
0.91 0.89 0.89 3.00 0.88 0.88 0.75 0.71 0.70 4.00 0.87 0.83 0.80
0.81 0.79 5.00 0.97 0.95 0.95 0.94 0.96 6.00 0.79 0.76 0.60 0.60
0.54 0.56 7.00 0.89 0.81 0.75 0.73 0.71 0.68 0.70 8.00 0.90 0.94
0.94 0.94 0.94 0.95 0.95 9.00 0.86 0.86 0.82 0.82 0.85 0.86 10.00
0.98 0.99 0.95 0.94 Mean 0.90 0.90 0.88 0.86 0.84 0.82 0.81 0.82
0.82 2SEM 0.04 0.08 0.13 0.11 0.07 0.10 0.11 0.10 0.27 BL UTP UTP
UTP UTP UTP UTP UTP UTP Patient UTP 10 20 40 80 160 240 320 400
1.00 1.01 0.89 0.90 0.90 2.00 0.92 0.90 0.89 0.89 0.92 3.00 0.88
0.73 0.73 0.73 0.72 4.00 0.85 0.79 0.79 0.79 0.77 5.00 1.01 0.88
0.86 0.87 0.86 6.00 0.78 0.56 0.56 0.55 0.56 0.56 7.00 0.84 0.72
0.71 0.72 0.71 0.71 0.69 8.00 0.94 0.95 0.95 0.95 0.97 0.92 0.90
9.00 0.89 0.84 0.83 0.83 0.83 0.84 10.00 Mean 0.90 0.84 0.83 0.83
0.78 0.79 0.79 0.79 0.79 2SEM 0.05 0.14 0.24 0.13 0.10 0.08 0.11
0.08 0.23
Dose Response Curve of Intracoronary Adenosine Vs. UTP
[0191] These results collectively suggest that IC continuous UTP
infusion using an IC microcatheter may be safe and useful for
inducing optimal coronary hyperemia for the individual patient
without any additional procedure. There are no obvious
contraindications or cautions to consider since UTP carries no side
effects; UTP is more receptor selective and has a faster and
slightly longer steady state; UTP produces maximal hyperemia, which
is close to post occlusion hyperemia, thus allowing for a more
accurately estimate of maximal coronary blood flow and rendering a
more precise FFR calculation.
[0192] Not only can UTP be used in all patients following normal
guidelines for FFR use, it can be further extended to include those
patients who have contraindications to the use of adenosine and who
for this reason would not normally be FFR tested.
Example 4
Systemic Infusion of UTP in Pigs for Using UTP as a Coronary, Renal
or Peripheral Dilator in Diagnostic Hyperemic Methods
[0193] In the present study, the hemodynamic response in the
pulmonary and systemic circulation was tested, as well as the
effect of central intravenous infusions of ATP, ADP, ADO, and UTP
on the heart.
[0194] Infusion rates were aimed at exerting a pronounced systemic
response in the lowering of arterial blood pressure, but avoiding a
total circulatory collapse.
Methods: 10 healthy female pigs (Department of Experimental
Medicine and Surgery, University of Copenhagen, Denmark) bred as a
combination of the Danish Landrace (1/3) and Yorkshire (2/3), with
a medium weight of 41.+-.2 kg were investigated.
[0195] Mean arterial blood pressure (MAP) was obtained from the
catheter in arcus aorta with the transducer (Pressure Monitoring
Kit, Baxter, Deerfield, Ill., USA) positioned at the level of the
heart. The left femoral artery was subsequently exposed and an
ultrasound doppler probe attached for peripheral femoral artery
flow measurements (CM-4000, Cardiomed, Norway). MAP, HR and
peripheral flow were monitored and data continuously collected
using a PowerLab system (Adinstruments, Australia). Cardiac Output
(CO) was determined in triplicates by thermodilution, following an
injection of 10 ml of cooled saline solution. Blood samples were
withdrawn from catheters in aorta and the right atrium at baseline
and at steady state when MAP had decreased maximally or by
.about.50%. Calculated variables were: stroke volume of the heart
(SV=CO/HR), pulmonary vascular resistance
(PVR=(MPAP-PCWP)/CO),systemic vascular resistance
(SVR=(MAP-MRAP)/CO), leg vascular conductance (LVC=LBF/(MAP-MRAP)),
and arterial (aorta) and mixed venous (pulmonary artery) oxygen
content (Hb*1.34*O.sub.2 saturation). In the calculation of LVC,
MRAP was used as an estimate of mean femoral venous pressure
(MFVP), as MRAP was found in a series of measurements to equal
MFVP, as estimated in 10 supine pigs. As a potential estimate for
myocardial oxygen demand the rate pressure product (RPP=MAP*HR) was
also calculated.
[0196] Drug infusions: Each animal was administered the nucleotides
ATP, UTP, ADP (Sigma, St. Louis, Mo., USA) and ADO (Item
Development AB, Stocksund, Sweden), through the internal jugular
vein in the right atrium, in random order following blinded
allocation. The nucleotides and ADO were prepared by dissolving in
saline so as to achieve the target concentration of ATP (40.+-.0.5
.mu.mol/min), ADP (43.+-.8 .mu.mol/min), UTP (up to 1,600
.mu.mol/min), and ADO (73.+-.7 .mu.mol/min). The nucleotides were
infused in increasing dosages at 2 min intervals aiming at reducing
MAP by maximally .about.50%. Thereafter, that specific infusion
rate was maintained for .about.3-5 min. After each intervention the
animal rested for .about.30 min, allowing resting cardiovascular
variables to be reestablished. Thereafter, a new cycle of
nucleotide infusion was administered. In the present study we aimed
to allow the drugs to reduce MAP by .about.50%, but without
inducing a hemodynamic and circulatory collapse, to simulate a
pronounced state of systemic vasodilation, as may be observed for
instance in a shock condition.
Results
Infusion Rates
[0197] There were no significant differences in any of the baseline
conditions before infusions of ATP, ADP, ADO or UTP (FIGS. 6 and
7). At target MAP, corresponding to a .about.50% reduction in
baseline MAP, ATP and ADP were infused at similar rates
(40.2.+-.0.5 and 43.2.+-.7.7 .mu.mol/min, p=ns), whereas ADO was
infused at a higher rate (72.7.+-.6.6 .mu.mol/min, p<0.05). A
further increase in ATP, ADP and ADO infusion rate, in contrary to
UTP, could lower MAP below the target .about.50% reduction in MAP,
requiring careful monitoring during dosage titration. In an attempt
for UTP to reach .about.50% reduction in MAP, UTP infusion rate was
increased as high as 1.600 .mu.mol/min in two animals. However, UTP
infusion did not decrease MAP more than .about.35%. This reduction
was also obtained at much lower UTP infusion rates (86.5.+-.18.2
.mu.mol/min). Since an increase in the dosage of UTP did not
decrease MAP further in those animals, the UTP infusion rate was
not increased beyond this dose in the remaining experiments, when
this drop in MAP was reached (FIG. 7a).
Nucleotides and their Effects on Pressures, Co, HR and SV. (FIG.
7)
[0198] During infusion of ATP, ADP and ADO, MAP was lowered by
47.4.+-.1.7, 48.4.+-.1.2 and 47.2.+-.1.5%, respectively, from
stable baseline values (p<0.05) (FIG. 7a). However, during UTP
infusion, MAP was only lowered by 35.0.+-.3.2% (p<0.05) (FIG.
7a). Furthermore ATP, ADO and UTP increased CO by 35.1.+-.6.9,
31.4.+-.9.9 and 72.5.+-.15.2%, respectively (p<0.05) (FIG. 7b).
ADP infusion did, however, not alter CO (p=ns). The CO increase
during UTP infusion was furthermore greater than the increase in CO
during infusion of ATP and ADO (p<0.05). In addition, ATP, ADP
and UTP increased HR with 23.0.+-.5.7, 26.6.+-.4.6 and
51.1.+-.9.0%, respectively, from stable baseline values (p<0.05)
(FIG. 7c). ADO however, did not increase (p=ns) HR. The increase in
HR was also greater for UTP than for the other nucleotides
(p<0.05). ATP, ADO and UTP infusion did not significantly change
SV (p=ns) (FIG. 7d). However, ADP infusion decreased SV by
21.1.+-.5.6% (p<0.05).
Nucleotides and their Effects on Vascular Resistance, Conductance
and Blood Flow.
[0199] ATP and ADO infusion decreased PVR by 37.8.+-.4.9 and
34.3.+-.2.6%, respectively, from stable baseline values (p<0.05)
(FIG. 7a). There was no significant difference (p=ns) in the PVR
change between the ATP and ADO infusions. UTP did not significantly
alter (p=ns) PVR. On the contrary, ADP markedly increased PVR by
156.7.+-.38.3% (p<0.05). PVR furthermore rose early in the ADP
titration procedure even during low infusion rates and continued to
increase dose dependently to 7.3.+-.1.2 Wood Unit (p<0.05).
[0200] ATP, ADP, ADO and UTP infusion all decreased SVR by
61.6.+-.2.1, 49.5.+-.2.0, 59.0.+-.3.0 and 62.9.+-.2.6%,
respectively, from stable baseline values (p<0.05) (FIG. 3b).
There was no significant difference (p=ns) in the SVR change
between trials. ATP, ADP and ADO decreased LBF by 22.7.+-.4.2,
34.9.+-.10.2 and 19.4.+-.10.7%, respectively, from stable baseline
values (p<0.05) (FIG. 6b). UTP however increased LBF by
53.7.+-.17.8% (p<0.05). There was no difference (p=ns) in the
change in LBF between these trials (FIG. 6c). LVC showed a tendency
to increase for all nucleotides, but this increase was only
significant for ATP, ADO and UTP (p<0.05); with an increase by
44.7.+-.8.7, 56.4.+-.12.9 and 150.0.+-.17.1%, respectively, from
stable baseline values (p<0.05). UTP increased LVC more than the
other nucleotides (p<0.05).
The Vasoactive Effect of ADP, ATP, UTP and Adenosine in the Leg
(FIG. 6)
[0201] The vasodilator potency in the peripheral circulation
revealed that ADP>ATP=ADO. Thus ATP, ADP and ADO decreased LBF
with 22.7.+-.4.2, 34.9.+-.10.2 and 19.4.+-.10.7%, respectively,
from stable baseline values (p<0.05). UTP however increased LBF
by 53.7.+-.17.8% (p<0.05) (FIG. 6c), presumably because of a
high increase in CO and a lesser degree of systemic pressure
reduction. LVC showed a tendency to increase for all nucleotides,
but this increase was only significant for ATP, ADO and UTP; with
an increase by 44.7.+-.8.7, 56.4.+-.12.9 and 150.0.+-.17.1%,
respectively, from stable baseline values (p<0.05).
[0202] The study identified the unique differential properties of
the nucleotides ATP, ADP, ADO and UTP in the pulmonary, peripheral
and systemic circulation. This is the first study to simultaneous
compare the vasodilatory potency of nucleotides when infused in the
right atrium. Previous studies have shown that ATP, ADP, ADO and
UTP all induce local vasodilation when infused in the femoral
artery and intravenous infusions can mediate a decreases in MAP but
none of these studies have compare the relative potency of all of
these nucleotides. With regards to the dose of the nucleotides
needed to reduce MAP by .about.50%, no difference in potency was
observed for ATP and ADP, despite different purinergic receptor
affiliation; where ADP predominantly stimulates P2Y.sub.1,
P2Y.sub.12 and P2Y.sub.13 receptors; and ATP predominantly
stimulates P2X, P2Y.sub.2, P2Y.sub.4 and P2Y.sub.11 receptors. ADO,
predominantly stimulating P1 receptors, was less potent than ADP
and ATP, thus requiring a higher infusion rate to produce the same
decrease in MAP. This makes it unlikely that the effect of ATP and
ADP was due to the dephosphorylated metabolites of these
substances. UTP, stimulating P2Y.sub.2 and P2Y.sub.4 receptors, was
unable to produce the targeted .about.50% drop in MAP, due to a
marked dose dependent rise in HR and CO. These results differs from
previous findings with intra-arterial nucleotide infusions, where
ATP and UTP were found to be equipotent, and even more potent than
ADO and ADP. This may be due to that the passage of the nucleotides
through the pulmonary and coronary circulation affects the MAP
response, differently from when infused intra-arterially.
[0203] The study also showed that UTP do not change PVR, despite an
increase in MPAP, as it was counterbalanced by an increase in CO,
at an unaltered PCWP. Previous studies have also suggested that
ATP, but not UTP, mediate vasodilation in the pulmonary artery, in
the presence of a functional endothelium. Although previous studies
have shown that ATP and UTP increase myocardial contractility,
probably through P2X, P2Y2, P2Y6 and P2Y11-like receptors the
present study only detected CO increases during infusions of ATP,
ADO and UTP; and to the greatest extent for UTP. ATP, ADP and UTP
all increase HR, whereas ADO do not change HR significantly. UTP
furthermore increases HR significantly more than ATP and ADP.
[0204] Relevance for diagnostic use: These results collectively
suggest that when UTP is infused intravenously in the systemic
circulation it: increases cardiac output (CO) by .about.70% due to
increases in HR, thus resembling an exercise condition; it has a
tendency to decrease rate pressure product by .about.10%, thereby
being safe for patients with ischemia; and importantly does not
produce arrhythmias (missed beats, VT, SVT or AV nodal block).
Furthermore, UTP increases leg blood flow by .about.50% presumably
because of a higher increase in CO (such as during exercise) and
has a lesser degree of systemic pressure reduction compared to
other adenine compounds, making it suitable for use with
indications such as aorta stenosis, peripheral arterial disease
(PAD), or kidney stenosis with methods such as myocardial perfusion
imaging, echo or MRI). Furthermore, because it increases leg
vascular conductance by .about.150% (only .about.50% with
adenosine), UTP is ideal for PAD diagnosis because it mimics
exercise-induced vasodilatation.
Example 5
[0205] The following data demonstrate that a 0.05 difference in FFR
between adenosine and UTP with a standard deviation of 0.15-0.17
represents a statistically significant difference (p=0.003).
[0206] If we were planning a study of a continuous response
variable from matched pairs of study subjects, the prior data
indicate that the difference in the response of matched pairs is
normally distributed with a standard deviation of 0.16. If the true
difference in the mean response of matched pairs is 0.05, we will
need to study only 135 pairs of subjects to be able to reject the
null hypothesis that this response difference is zero with
probability (power) 0.95. The Type I error probability associated
with this test of this null hypothesis is 0.05.
TABLE-US-00003 FFR BL Adenosine BL UTP Mean 0.89 0.77 0.88 0.72 SD
0.1 0.15 0.12 0.17 2SD 0.2 0.31 0.24 0.34 Ttest 0.0034
[0207] The cut-off value for FFR is usually 0.8 for being
indicative of a treatment intervention being required (according to
the set FFR value in the FAME study). This means that if patients
have a FFR>0.8, they can be left untreated, however if the value
is <0.8, they should be subjected to a PCI with insertion of a
stent or bypass surgery according to the lesion anatomy
[0208] For the guiding catheter study, a FFR set at 50.75 or 50.8
would require altered treatment regiments in the below percentage
of patients with:
TABLE-US-00004 240 .mu.g/min (n = 23) FFR .ltoreq. 0.8 Ado (% of
patients) 43% Utp (% of patients) 65% FFR .ltoreq. 0.75 Ado (% of
patients) 39% Utp (% of patients) 47%
[0209] Consequently, by using UTP in accordance with the present
invention, it would be possible to diagnose more people than by the
known use of adenosine regardless of the set cut-off value for the
same concentration.
[0210] As seen from the microcatheter study, a FFR set at 50.8
would require altered treatment regiments in the below percentage
of patients in the different concentration:
TABLE-US-00005 80 .mu.g/min 160 .mu.g/min 320 .mu.g/min 400
.mu.g/min FFR .ltoreq. 0.8 (n = 8) (n = 6) (n = 9) (n = 3) Ado (%
of 37 33 44 33 patients) Utp (% of 62 50 44 33 patients)
[0211] Although it may seem as if ado=UTP for the higher
concentrations, the estimate of FFR is always based on the lowest
possible FFR, because only at this point is there maximal hypermia
which corresponds to the correct perfusion pressure.
Example 6
(Prophetic) Use of UTP, a Derivative Thereof, or a Salt Thereof to
Diagnose Renal Artery Stenosis
[0212] When a renal arterial stenosis is identified on an
arteriogram, intra-arterial systemic pressure can be measured
continuously with a transducer and a miniaturized pressure-gradient
wire system (PressureWire; St. Jude Medical or Volcano combo wire).
Pressures can be recorded using a fiber-optic pressure sensor
located laterally and 3 cm from the distal end. The basic principle
is that the element modulates an optical reflection with
pressure-induced elastic movements. This pressure wire thus
replaces a standard 0.018-inch guide wire. After advancing a 4 to
7-F guiding catheter from the femoral artery to the ostium of the
renal artery, a "coronary" 0.014-inch wire is introduced into the
guiding catheter and moved to the ostium of the stenosis. A
pressure gradient across renal arteries can be assessed when
combined with an infusion of UTP, a derivative thereof, or a salt
thereof to induce renal hyperemia. Infusion of adenosine will,
under these circumstances, constrict the afferent arterioles,
causing dose-dependent renal vasoconstriction, whereas UTP produces
the desired renal vasodilatation. After identical pressure of the
guiding catheter and the wire is confirmed at this position, the
stenosis can be traversed by means of the floppy-ended wire,
followed by the transducer. Dilation equipment can then be inserted
through the guiding catheter and across the stenosis, leaving the
wire in place. Immediately after the intervention, results can be
tested using another infusion of UTP, a derivative thereof, or a
salt thereof. The pressure gradient is thus measured with the wire
before and during the infusion.
[0213] Patients with a renal artery stenosis with a Pd/Pa ratio
larger than 0.90 can be considered hemodynamically insignificant,
and it is unlikely that renal angioplasty would be useful in such
patients even though percent diameter stenosis is larger than 50%.
Conversely, renal artery stenoses with a Pd/Pa ratio <0.90
should be considered hemodynamically significant regardless of
angiographic severity. Furthermore, a combined catheter with
pressure and UTP infusion could ensure a local infusion of the
compound to prevent systemic spill over in patients.
[0214] All patent and non-patent references cited in the
application are hereby incorporated by reference in their
entirety.
REFERENCES
[0215] WO 2007/065437 [0216] U.S. Pat. No. 5,292,498 [0217] U.S.
Pat. No. 5,789,391 [0218] U.S. Pat. No. 5,837,861 [0219] 1 Erlinge
D, Burnstock G: P2 receptors in cardiovascular regulation and
disease. Purinergic signalling 2008; 4:1-20. [0220] 2 Burnstock G,
Ralevic V: New insights into the local regulation of blood flow by
perivascular nerves and endothelium. British journal of plastic
surgery 1994; 47:527-543. [0221] 3 Jeremias A, Filardo S D,
Whitbourn R J, Kernoff R S, Yeung A C, Fitzgerald P J, Yock P G:
Effects of intravenous and intracoronary adenosine 5'-triphosphate
as compared with adenosine on coronary flow and pressure dynamics.
Circulation 2000; 101:318-323. [0222] 4 Jeremias A, Whitbourn R J,
Filardo S D, Fitzgerald P J, Cohen D J, Tuzcu E M, Anderson W D,
Abizaid A A, Mintz G S, Yeung A C, Kern M J, Yock P G: Adequacy of
intracoronary versus intravenous adenosine-induced maximal coronary
hyperemia for fractional flow reserve measurements. American heart
journal 2000; 140:651-657. [0223] 5 Kato M, Shiode N, Teragawa H,
Hirao H, Yamada T, Yamagata T, Matsuura H, Kajiyama G: Adenosine
5'-triphosphate induced dilation of human coronary microvessels in
vivo. Internal medicine (Tokyo, Japan) 1999; 38:324-329. [0224] 6
Sonoda S, Takeuchi M, Nakashima Y, Kuroiwa A: Safety and optimal
dose of intracoronary adenosine 5'-triphosphate for the measurement
of coronary flow reserve. American heart journal 1998; 135:621-627.
[0225] 7 Tobis J, Azarbal B, Slavin L: Assessment of intermediate
severity coronary lesions in the catheterization laboratory.
Journal of the American College of Cardiology 2007; 49:839-848.
[0226] 8 Yoon M H, Tahk S J, Yang H M, Park J S, Zheng M, Lim H S,
Choi B J, Choi S Y, Choi U J, Hwang J W, Kang S J, Hwang G S, Shin
J H: Comparison of the intracoronary continuous infusion method
using a microcatheter and the intravenous continuous adenosine
infusion method for inducing maximal hyperemia for fractional flow
reserve measurement. American heart journal 2009; 157:1050-1056.
[0227] 9 Rosenmeier J B, Yegutkin G G, Gonzalez-Alonso J:
Activation of atp/utp-selective receptors increases blood flow and
blunts sympathetic vasoconstriction in human skeletal muscle. The
Journal of physiology 2008; 586:4993-5002. [0228] 10 Rosenmeier J
B, Hansen J, Gonzalez-Alonso J: Circulating atp-induced
vasodilatation overrides sympathetic vasoconstrictor activity in
human skeletal muscle. The Journal of physiology 2004; 558:351-365.
[0229] 11 Hrafnkelsdottir T, Erlinge D, Jern S: Extracellular
nucleotides atp and utp induce a marked acute release of
tissue-type plasminogen activator in vivo in man. Thrombosis and
haemostasis 2001; 85:875-881. [0230] 12 Thaning P, Bune L T,
Hellsten Y, Pilegaard H, Saltin B, Rosenmeier J B: Attenuated
purinergic receptor function in patients with type 2 diabetes.
Diabetes; 59:182-189. [0231] 13 Borna C, Wang L, Gudbjartsson T,
Karlsson L, Jern S, Malmsjo M, Erlinge D: Contractions in human
coronary bypass vessels stimulated by extracellular nucleotides.
The Annals of thoracic surgery 2003; 76:50-57. [0232] 14 Malmsjo M,
Adner M, Harden T K, Pendergast W, Edvinsson L, Erlinge D: The
stable pyrimidines udpbetas and utpgammas discriminate between the
p2 receptors that mediate vascular contraction and relaxation of
the rat mesenteric artery. British journal of pharmacology 2000;
131:51-56. [0233] 15 Malmsjo M, Hou M, Harden T K, Pendergast W,
Pantev E, Edvinsson L, Erlinge D: Characterization of contractile
p2 receptors in human coronary arteries by use of the stable
pyrimidines uridine 5'-o-thiodiphosphate and uridine
5'-o-3-thiotriphosphate. The Journal of pharmacology and
experimental therapeutics 2000; 293:755-760. [0234] 16 Matsumoto T,
Nakane T, Chiba S: Utp induces vascular responses in the isolated
and perfused canine epicardial coronary artery via utp-preferring
p2y receptors. British journal of pharmacology 1997; 122:1625-1632.
[0235] 17 Seye C I, Kong Q, Erb L, Garrad R C, Krugh B, Wang M,
Turner J T, Sturek M, Gonzalez F A, Weisman G A: Functional p2y2
nucleotide receptors mediate uridine 5'-triphosphate-induced
intimal hyperplasia in collared rabbit carotid arteries.
Circulation 2002; 106:2720-2726. [0236] 18 Shen J, Seye C I, Wang
M, Weisman G A, Widen P A, Sturek M: Cloning, up-regulation, and
mitogenic role of porcine p2y2 receptor in coronary artery smooth
muscle cells. Molecular pharmacology 2004; 66:1265-1274. [0237] 19
Pillois X, Chaulet H, Belloc I, Dupuch F, Desgranges C, Gadeau A P:
Nucleotide receptors involved in utp-induced rat arterial smooth
muscle cell migration. Circulation research 2002; 90:678-681.
[0238] 20 Chaulet H, Desgranges C, Renault M A, Dupuch F, Ezan G,
Peiretti F, Loirand G, Pacaud P, Gadeau A P: Extracellular
nucleotides induce arterial smooth muscle cell migration via
osteopontin. Circulation research 2001; 89:772-778. [0239] 21 Seye
C I, Yui N, Jain R, Kong Q, Minor T, Newton J, Erb L, Gonzalez F A,
Weisman G A: The p2y2 nucleotide receptor mediates utp-induced
vascular cell adhesion molecule-1 expression in coronary artery
endothelial cells. The Journal of biological chemistry 2003;
278:24960-24965. [0240] 22 Tonino P A, De Bruyne B, Pijls N H,
Siebert U, Ikeno F, van' t Veer M, Klauss V, Manoharan G, Engstrom
T, Oldroyd K G, Ver Lee P N, MacCarthy P A, Fearon W F: Fractional
flow reserve versus angiography for guiding percutaneous coronary
intervention. The New England journal of medicine 2009;
360:213-224. [0241] 23 McGeoch R J, Oldroyd K G: Pharmacological
options for inducing maximal hyperaemia during studies of coronary
physiology. Catheter Cardiovasc Intery 2008; 71:198-204. [0242] 24
De Bruyne B, Manoharan G, Pijls N H, Verhammei K, Madaric J,
Bartunek J, Vanderheyden M, Heyndrickx G R: Assessment of renal
artery stenosis severity by pressure gradient measurements. Journal
of the American College of Cardiology 2006; 48:1851-1855. [0243] 25
Trochu J N, Zhao G, Post H, Xu X, Belardinelli L, Belloni F L,
Hintze T H: Selective a2a adenosine receptor agonist as a coronary
vasodilator in conscious dogs: Potential for use in myocardial
perfusion imaging. Journal of cardiovascular pharmacology 2003;
41:132-139. [0244] 26 Wangensteen R, Fernandez O, Sainz J, Quesada
A, Vargas F, Osuna A: Contribution of endothelium-derived relaxing
factors to p2y-purinoceptor-induced vasodilation in the isolated
rat kidney. General pharmacology 2000; 35:129-133. [0245] 27 Ko H,
Carter R L, Cosyn L, Petrelli R, de Castro S, Besada P, Zhou Y,
Cappellacci L, Franchetti P, Grifantini M, Van Calenbergh S, Harden
T K, Jacobson K A: Synthesis and potency of novel uracil
nucleotides and derivatives as p2y2 and p2y6 receptor agonists.
Bioorganic & medicinal chemistry 2008; 16:6319-6332. [0246] 28
Bokhari S, Ficaro E P, McCallister B D, Jr.: Adenosine stress
protocols for myocardial perfusion imaging. J Nucl Cardiol 2007;
14:415-416. [0247] 29 Futamatsu H, Wilke N, Klassen C, Angiolillo D
J, Suzuki N, Kawaguchi R, Shoemaker S, Siuciak A, Bass T A, Costa M
A: Usefulness of cardiac magnetic resonance imaging for coronary
artery disease detection. Minerva cardioangiologica 2007;
55:105-114. [0248] 30 Douglas P S, Khandheria B, Stainback R F,
Weissman N J, Peterson E D, Hendel R C, Stainback R F, Blaivas M,
Des Prez R D, Gillam L D, Golash T, Hiratzka L F, Kussmaul W G,
Labovitz A J, Lindenfeld J, Masoudi F A, Mayo P H, Porembka D,
Spertus J A, Wann L S, Wiegers S E, Brindis R G, Douglas P S,
Hendel R C, Patel M R, Peterson E D, Wolk M J, Allen J M:
Accf/ase/acep/aha/asnc/scai/scct/scmr 2008 appropriateness criteria
for stress echocardiography: A report of the american college of
cardiology foundation appropriateness criteria task force, american
society of echocardiography, american college of emergency
physicians, american heart association, american society of nuclear
cardiology, society for, cardiovascular angiography and
interventions, society of cardiovascular computed tomography, and
society for cardiovascular magnetic resonance endorsed by the heart
rhythm society and the society of critical care medicine. Journal
of the American College of Cardiology 2008; 51:1127-1147. [0249] 31
Beanlands R S, Chow B J, Dick A, Friedrich M G, Gulenchyn K Y,
Kiess M, Leong-Poi H, Miller R M, Nichol G, Freeman M, Bogaty P,
Honos G, Hudon G, Wisenberg G, Van Berkom J, Williams K, Yoshinaga
K, Graham J: Ccs/car/canm/cncs/canscmr joint position statement on
advanced noninvasive cardiac imaging using positron emission
tomography, magnetic resonance imaging and multidetector computed
tomographic angiography in the diagnosis and evaluation of ischemic
heart disease--executive summary. The Canadian journal of
cardiology 2007; 23:107-119.
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